The Queensland Trias (Burrum Formation) contains a solitary species of bivalved mollusca, Corbicula burrumensis. This genus is generally found associated with freshwater or brackish conditions.

In New Zealand marine Triassic beds occur, containing, amongst other genera, a species of Leda. In the succeeding Wairoa Series the interesting fossil, Daonella lommeli occurs. This shell is typical of the Norian (Upper Trias) of the Southern Tyrol. Above the Daonella bed occurs the Trigonia bed, with that genus and Edmondia. In the next younger stage, the Otapiri Series, near Nelson, there are fine-grained sandstones packed full of the remains of Mytilus problematicus (Fig. 93 B) and Monotis salinaria (Fig. 93 C), the latter also a Norian fossil.

Jurassic Bivalves.—

Jurassic bivalved molluscs are plentiful in the W. Australian limestones, as at Greenough River. Amongst others may be mentioned Cucullaea semistriata, Ostrea, Gryphaea, Trigonia moorei (Fig. 93 D), Pecten cinctus, Ctenostreon pectiniforme and Astarte cliftoni (Fig. 93 E). Several of the species found are identical with European Jurassic fossils.

Jurassic strata in Victoria, being of a freshwater and lacustrine nature, yield only species of Unio, as U. dacombei, and U. stirlingi.

The Jurassic beds of S. Australia contain a species of Unio named U. eyrensis. In the same strata which contains this shell, plant remains are found, as Cladophlebis and Thinnfeldia, two well-known types of Jurassic ferns.

Lower Cretaceous Bivalves.—

In Queensland the Lower Cretaceous limestones and marls contain a large assemblage of bivalves, the more important of which are Nucula truncata (Fig. 94 A), Maccoyella reflecta (Fig. 94 B), M. barkleyi, Pecten socialis and Fissilunula clarkei (Fig. 94 C), from Wollumbilla; and Inoceramus pernoides, I. carsoni and Aucella hughendenensis from the Flinders River (the latter also from New South Wales).

In the Lake Eyre District of S. Australia we find Maccoyella barkleyi, which also occurs in Queensland and New South Wales (at White Cliffs), Trigonia cinctuta, Mytilus rugocostatus and Modiola eyrensis. The handsome bivalve, Pleuromya plana occurs near Broome in W. Australia.

Upper Cretaceous Bivalves.—

The Upper Cretaceous or Desert Sandstone at Maryborough, Queensland, has yielded amongst others, the following shells:—(Nucula gigantea, Maccoyella reflecta also found in the Lower Cretaceous of Queensland, New South Wales and S. Australia), and Fissilunula clarkei (also found in the L. Cretaceous of New South Wales, Queensland and S. Australia). Some of these beds, however, which were hitherto believed to belong to the Upper and Lower Series respectively may yet prove to be on one horizon—the Lower Cretaceous. Cyrenopsis opallites (Fig. 94 E) of White Cliffs, New South Wales, appears to be a truly restricted Upper Cretaceous species.

The Cretaceous of New Zealand (Amuri System) contains Trigonia sulcata, Inoceramus sp. and the curious, contorted shell, Conchothyra parasitica (Fig. 94 F) which is related to Pugnellus, a form usually considered as a sub-genus of Strombus.

From Papua an Inoceramus has been recorded from probable Cretaceous beds.

Cainozoic Bivalves.—

In Victoria, South Australia, and the N.W. of Tasmania, as well as in New Zealand, Cainozoic marine beds are well developed, and contain an extensive bivalved molluscan fauna. Of these fossils only a few common and striking examples can here be noticed, on account of the limits of the present work.

The commonest genera are:—Ostrea, Placunanomia, Dimya, Spondylus, Lima, Pecten, Arca, Barbatia, Plagiarca, Cucullaea, Glycimeris, Limopsis, Nucula, Leda, Trigonia, Cardita, Cuna, Crassatellites, Cardium, Protocardium, Chama, Meretrix, Venus (Chione), Dosinea, Gari, Mactra, Corbula, Lucina, Tellina, Semele and Myodora.

To mention a few species of persistent range, from Balcombian to Kalimnan, we may cite the following from the Cainozoic of southern Australia:—Dimya dissimilis (Fig. 95 A), Spondylus pseudoradula (Fig. 95 B), Lima (Limatula) jeffreysiana, Pecten polymorphoides (found also in the Oamaru Series, New Zealand) (Fig. 95 C), Amusium zitteli (found also in both the Waimangaroa and Oamaru Series of New Zealand), Barbatia celleporacea, Cucullaea corioensis, Limopsis maccoyi, Nucula tenisoni, Leda vagans (Fig. 95 D), Corbula ephamilla and Myodora tenuilirata.

Balcombian Bivalves.—

On the other hand, many species have a restricted range, and these are invaluable for purposes of stratigraphical correlation. For example, in the Balcombian we have Modiola praerupta (Fig. 95 E), Modiolaria balcombei, Cuna regularis, Cardium cuculloides, Cryptodon mactraeformis, Verticordia pectinata and V. excavata.

In the Janjukian Series restricted forms of bivalves are exceptionally numerous, amongst them being:—Dimya sigillata, Plicatula ramulosa, Lima polynema, Pecten praecursor, P. eyrei, P. gambierensis, Pinna cordata, Modiola pueblensis (Fig. 96 A), Arca dissimilis, Limopsis multiradiata, L. insolita, Leda leptorhyncha, L. crebrecostata, Cardita maudensis, C. tasmanica (Fig. 96 B), Cuna radiata, Lepton crassum, Cardium pseudomagnum, Venus (Chione) multitaeniata, Solenocurtus legrandi, Lucina planatella (Fig. 96 C), Tellina porrecta and Myodora lamellata.

In Papua a Pecten (P. novaeguineae) has been recorded from the ? Lower Pliocene of Yule Island.

Kalimnan Bivalves.—

The Kalimnan beds contain the following restricted or upward ranging species:—Ostrea arenicola, O. manubriata (Fig. 96 D), Pecten antiaustralis (also in the Werrikooian Series), Perna percrassa, Mytilus hamiltonensis, Glycimeris halli, Limopsis beaumariensis (also Werrikooian) (Fig. 96 E), Leda crassa (also living), Trigonia howitti, Cardita solida, C. calva (also living), Erycina micans, Meretrix paucirugata, Sunetta gibberula, Venus (Chione) subroborata (Fig. 96 F), Donax depressa, Corbula scaphoides (also living), Barnea tiara, Lucina affinis, Tellina albinelloides and Myodora corrugata.

Werrikooian Bivalves.—

The next stage, the Werrikooian (Upper Pliocene), contains a large percentage of living species, as Ostrea angasi, Placunanomia ione (ranging down into Janjukian), Glycimeris radians, Leda crassa (also a common Kalimnan fossil), various species of Venus (Chione), as V. strigosa and V. placida, and Barnea australasiae.

Pleistocene Bivalves.—

The bivalved shells of the Pleistocene are similar to those now found living round the Australian coast, as Pecten asperrimus, Mytilus latus, Leda crassa, Soletellina biradiata and Spisula parva.

Pleistocene shells of bivalved genera occur in the coastal hills of Papua, including the following:—Cultellus, Corbula, Mactra, Tellina, Venus (Chione), Dione, Dosinea, Leda and Arca.

The SCAPHOPODS (“digger foot”) or the “Elephant-tusk shells” are adapted, by their well-developed foot, to burrow into the mud and sand.

Devonian Scaphopods.—

This group of mollusca makes its first appearance in Australasian sediments in the Middle Devonian (Murrumbidgee beds) of New South Wales, represented by Dentalium tenuissimum.

Jurassic Scaphopods.—

In the Jurassic strata of the Mataura Series of New Zealand, Dentalium huttoni (Fig. 97 A) occurs at the Kowhai River and Wilberforce.

Cretaceous Scaphopods.—

Dentalium wollumbillensis occurs in the drab and dark-coloured limestones of the Lower Cretaceous of the Lake Eyre Basin in S. Australia, and the same species is also found in the Lower Cretaceous (Rolling Downs Formation) of Wollumbilla, Queensland.

Cainozoic Scaphopods.—

The Cainozoic beds both of New Zealand and southern Australia yield many species of Dentalium, the commonest and most widely distributed being the longitudinally ribbed D. mantelli (Fig. 97 B), which ranges from the Balcombian to the Werrikooian stages in Australia, and is also typical of the Oamaru Series in New Zealand, where it is accompanied by the ponderous species, D. giganteum, which attained a length of over six inches. Another form common in our Cainozoics is the smooth-shelled D. subfissura; this also has a wide range, namely Balcombian to Kalimnan.

Palaeozoic Chitons.—

The POLYPLACOPHORA or Chitons (“Mail-shells”), first appeared in the Ordovician. In Australia Chelodes calceoloides (Fig. 97 C) is found in the Silurian of Derrengullen Creek, Yass, New South Wales; and another species of the genus is found in beds of the same age at Lilydale, Victoria. Between that period and the Cainozoic or Tertiary there is a gap in their history in Australia.

Cainozoic Chitons.—

Ischnochiton granulosus (Fig. 97 D) is a Balcombian species of the modern type of “mail-shell,” occurring not infrequently in the clays of Balcombe’s Bay, Port Phillip, Victoria. Cryptoplax pritchardi (Fig. 97 E) is a curious form belonging to the attenuated, worm-like group of the Cryptoplacidae, until lately unknown in the fossil state; it is found in the Kalimnan Series near Hamilton, Victoria. Several other genera of the chitons are found fossil in the Australian Cainozoics which still live on our coasts, as Lorica, Plaxiphora and Chiton. The first-named genus is represented fossil by Lorica duniana from the Turritella bed (Janjukian) of Table Cape, Tasmania.

Characters of Gasteropoda.—

The GASTEROPODA (“belly-foot”) or univalve shells possess a muscular foot placed beneath the stomach and viscera. In the Heteropoda this foot is modified as a vertical fin, and in the Pteropoda as two wing-like swimming membranes close to the head. The mantle lobe is elevated along the back like a hood, and its surfaces and edges secrete the shell which contains the animal. The shell is typically a cone (example, Patella or Limpet) which is often spirally coiled either in a plane (ex. Planorbis), conically turbinoid (ex. Trochus), or turreted (ex. Turritella). The body and shell are attached by muscles, the spiral forms being attached to the columella or axial pillar, and the bowl-shaped forms to the inner surface of the shell.

Gasteropod shells are normally right-handed (dextral), but a few genera as Clausilia, Bulinus and Physa, are left-handed (sinistral). The height or length of the shell is measured from the apex to the lower margin of the mouth. In coiled shells we may regard them as a more or less elongated cone wound round a central pillar, the columella, or around a central tube. A turn or coil of the shell is a whorl, and together, with the exception of the last, form the spire. The line between two adjacent whorls is the suture. When the columella is solid the shell is said to be imperforate, and when a central tube is left by the imperfect fusion of the whorls, it is perforate. The opening of the tubular columella is termed the umbilicus, and this is sometimes contracted by the encroachment of shell matter termed the callus. The aperture is entire when the rim is uninterrupted; and channelled when there is a basal notch, where the siphon which conducts water to the gills is lodged.

As a rule the large heavy gasteropods inhabit shallow water. The following living genera are characteristic of rocky shore-lines; Risella, Buccinum, Purpura and Patella. Genera typical of sandy shores are Nassa, Natica, Cypraea, Turritella and Scala.

Cambrian Gasteropods.—

From the Cambrian of South Australia Prof. Tate described some minute Gasteropods which he referred to the genera Stenotheca (S. rugosa, var. paupera), Ophileta (O. subangulata) (Fig. 98 A), and Platyceras (P. etheridgei). In these beds at Curramulka the following Pteropods were found by the same authority, viz., Salterella planoconvexa, Hyolithes communis (Fig. 98 C) and H. conularioides.

The Cambrian Limestone of the Kimberley District, W. Australia, contains the characteristic Pteropod Salterella hardmani (Fig. 98 B). The shell is a conical tube, straight or slightly curved, and measuring scarcely an inch in length.

The Upper Cambrian of the Mersey River District in Tasmania has afforded some doubtful examples of the genus Ophileta.

In the Upper Cambrian Limestones of the Dolodrook Valley, near Mt. Wellington, Victoria, a minute limpet shaped Gasteropod occurs, named Scenella tenuistriata (Fig. 98 D).

Ordovician Gasteropods.—

Ordovician limestones with fossil shells occur in the Leigh’s Creek District in South Australia, and also at Tempe Downs and Petermann and Laurie’s Creeks, W. of Alice Springs. The euomphaloid shell Ophileta gilesi was described from Laurie’s Creek, and Eunema larapinta from the Tempe Downs. A pleurotomarid, Raphistoma browni (Fig. 98) occurs near Leigh’s Creek, and at Laurie’s and Petermann Creeks. A Pteropod, Hyolithes leptus, has been described from the Lower Ordovician of Coole Barghurk Creek, near Meredith, Victoria.

Silurian Gasteropods.—

The Silurian Gasteropods are fairly well represented, especially in the upper stage, and are widely distributed throughout the Australian fossiliferous localities. Moreover, some of the species are identical with those found as far off as North America and Europe. In Victoria the shales and sandstones of the lower stage (Melbournian) contain the genera Bellerophon, Cyrtolites and Loxonema. The Pteropoda include Tentaculites, Coleolus, Hyolithes and Conularia (C. sowerbii (Fig. 99 F), a species also found in Great Britain). The Victorian limestones and mudstones of the upper stage (Yeringian) are somewhat rich in Gasteropods, such genera occurring as Pleurotomaria, Phanerotrema (with cancellated shell and large slit-band), Murchisonia, Gyrodoma, Bellerophon, Trematonotus (a spiral shell with a large trumpet-shaped mouth and a dorsal row of perforations in place of a slit-band), Euomphalus, Cyclonema, Trochus (Scalaetrochus), Niso (Vetotuba), Loxonema, Platyceras and Capulus. The section Pteropoda contains Tentaculites, Hyolithes and Conularia.

In Tasmania are found Raphistoma, Murchisonia, Bellerophon, Helicotoma, Trochonema and Tentaculites.

Devonian Gasteropods.—

The derived boulders of the White Cliffs opal field have been referred to the Devonian system, but of this there is some doubt, as the Gasteropods noted from these boulders closely resemble those of the Silurian fauna: they are Murchisonia Euomphalus (E. culleni), and Loxonema. The genus Murchisonia has also been recorded from the Baton River, New Zealand (Wangepeka Series) by MacKay.

The Middle Devonian Gasteropod fauna in Victoria, as found in the Buchan and Bindi Limestones, comprises Murchisonia, Trochus, and Platyceras.

In New South Wales the best known genera are Pleurotomaria, Murchisonia, Bellerophon, Euomphalus and Loxonema. The two latter genera have also been obtained at Barker Gorge, Western Australia.

Carboniferous Gasteropods.—

Carboniferous Gasteropoda have been found in New South Wales, belonging to the genera Gosseletina (G. australis) (Fig. 100 A) and Yvania (Y. konincki) (Fig. 100 B), both of which have their countertypes in the Carboniferous of Belgium. Y. konincki is also found in the Carbopermian (Gympie beds) of Rockhampton, Queensland, while Y. levellii is found in the Carbopermian of Western Australia.

Carbopermian Gasteropods.—

The Carbopermian gasteropods of New South Wales are Pleurotomaria (Mourlonia), Keeneia platyschismoides, Murchisonia, Euomphalus, Platyschisma (P. oculum) (Fig. 100 E), Loxonema and Macrocheilus. Examples of the genus Conularia are sometimes found, probably attaining a length, when complete, of 40 centimetres.

In Tasmania we find Conularia tasmanica, a handsome Pteropod, also of large dimensions. Platyschisma, Pleurotomaria (Mourlonia), Bellerophon and Porcellia are amongst the Carbopermian Gasteropods of Queensland.

In Western Australia Pleurotomaria (Mourlonia), Bellerophon, Euomphalus, Euphemus, Platyceras, and Loxonema occur in the Carbopermian.

Jurassic Gasteropods.—

Jurassic gasteropods are found sparingly in the limestone of the Geraldton District and other localities in Western Australia. The more important of these are Pleurotomaria (P. greenoughiensis), Turbo (T. australis) (Fig. 101 A) and Rissoina (R. australis) (Fig. 101 B).

The Queensland gasteropod fauna comprises Cinulia a typical Cretaceous genus, Actaeon and Natica. These occur in the Lower Cretaceous or Rolling Downs Formation. Cinulia is also found in South Australia at Lake Eyre with Natica (N. ornatissima) (Fig. 101 C). Pseudamaura variabilis (Fig. 101 D) is found in New South Wales, Queensland and South Australia; whilst Anchura wilkinsoni occurs in Queensland and South Australia.

In New Zealand the Waipara Greensands (Cretaceous) contain a species of Rostellaria (R. waiparensis) (Fig. 101 E).

Cainozoic Gasteropods.—

Cainozoic Gasteropods are exceedingly abundant in beds of that system in Australasia. The Cainozoic marine fauna in Australia is practically restricted to the States of Victoria, South Australia, and Tasmania; whilst New Zealand has many species in common with Australia.

Genera.—

The commonest genera of the marine Cainozoic or Tertiary deposits are:—Haliotis, Fissurellidea, Emarginula, Subemarginula, Astralium, Liotia, Gibbula, Eulima, Niso, Odostomia, Scala, Solarium, Crepidula, Calyptraea, Natica, Rissoa, Turritella, Siliquaria, Cerithium, Newtoniella, Tylospira, Cypraea, Trivia, Morio, Semicassis, Lotorium, Murex, Typhis, Columbella, Phos, Nassa, Siphonalia, Euthria (Dennantia), Fusus, Columbarium, Fasciolaria, Latirus, Marginella, Mitra, Volutilithes, Voluta, Harpa, Ancilla, Cancellaria, Terebra, Pleurotoma, Drillia, Conus, Bullinella and Vaginella.

Persistent Species.—

Amongst the Cainozoic Gasteropoda of southern Australia which have a persistent range through Balcombian to Kalimnan times, we find:—Niso psila, Crepidula unguiformis (also Werrikooian and Recent), Natica perspectiva, N. hamiltonensis, Turritella murrayana, Cerithium apheles, Cypraea leptorhyncha, Lotorium gibbum, Volutilithes antiscalaris (also in Werrikooian), Marginella propinqua, Ancilla pseudaustralis, Conus ligatus and Bullinella exigua.

Balcombian Gasteropods.—

Species restricted to the Balcombian stage include Scala dolicho, Seguenzia radialis, Dissocheilus eburneus, Trivia erugata, Cypraea ampullacea (Fig. 102 A), C. gastroplax, Colubraria leptoskeles, Murex didymus (Fig. 102 B), Eburnopsis aulacoessa (Fig. 102 C), Fasciolaria concinna, Mitra uniplica, Harpa abbreviata, Ancilla lanceolata, Cancellaria calvulata (Fig. 102 D), Buchozia oblongula, Pleurotoma optata, Terebra leptospira and Vaginella eligmostoma (Fig. 102 E), (also found at Gellibrand River).

Species of Gasteropods restricted to the Janjukian stage include:—Pleurotomaria tertiaria, Haliotis mooraboolensis, Liotia lamellosa, Thalotia alternata, Eutrochus fontinalis (Fig. 103 A), Astralium hudsonianum, Turbo atkinsoni, Odostomia polita, Scala lampra (Fig. 103 C), Natica gibbosa (Fig. 103 D) (also found in the Pareora Series of the Oamaru system and in the Wanganui beds of New Zealand), Calyptraea subtabulata, Turritella aldingae, Cerithiopsis mulderi, Cerithium flemingtonense, Cypraea platyrhyncha, C. consobrina, Morio wilsoni (Fig. 103 B), Lotorium abbotti, Murex otwayensis, Eburnopsis tesselatus, Tudicla costata, Latirus semiundulatus, Fusus meredithae, Columbarium spiniferum, Voluta pueblensis, V. heptagonalis, V. macroptera (also recorded from Hall’s Sound, Papua) (Fig. 103 E), Volutilithes anticingulatus (also from Papua), Harpa clathrata, Bela woodsi, Bathytoma paracantha and Volvulella inflatior.

Dolium costatum, allied to the “Fig-Shell” has been noted from the Cainozoic clays (? Lower Pliocene), Yule Island, Papua.

Species of Gasteropods restricted to the Kalimnan Stage, or only passing upwards include:—Bankivia howitti (Fig. 104 A), Liopyrga quadricingulata, Calyptraea corrugata, Natica subvarians, Turritella pagodula, Eglisia triplicata (Fig. 104 B), Tylospira clathrata, Cypraea jonesiana, Lotorium ovoideum, Sistrum subreticulatum, Voluta masoni (Fig. 104 C), Ancilla papillata (Fig. 104 D), Cancellaria wannonensis, Drillia wanganuiensis (also in the Petane Series of New Zealand), Terebra catenifera, T. geniculata (Fig. 104 E) and Ringicula tatei.

New Zealand Cainozoic Gasteropods.—

Characteristic Gasteropoda of the Oamaru Series in New Zealand are Pleurotomaria tertiaria (also in the Australian Janjukian), Scala lyrata, Natica darwinii, Turritella cavershamensis, Ancilla hebera (also in the Australian Balcombian and Janjukian) and Pleurotoma hamiltoni. Gasteropods of the Awatere Series in New Zealand are Natica ovata, Struthiolaria sulcata (Fig. 103 F), and Scaphella corrugata (found also in the Oamaru Series). The Putiki beds of the Petane Series in New Zealand contain Trophon expansus, Pisania drewi and Pleurotoma wanganuiensis.

Werrikooian Gasteropods.—

The marine gasteropods of the Werrikooian of southern Australia, as found at Limestone Creek, Glenelg River, Western Victoria, and the Moorabool Viaduct near Geelong, are nearly all living at the present time, with the exception of a few older Cainozoic species. Amongst these latter are Conus ralphi, Pleurotoma murndaliana, Volutilithes antiscalaris and Columbarium craspedotum.

Pleistocene Gasteropoda.—

The Pleistocene land mollusca, and especially the gasteropods of Australia, present some striking points of interest, for whilst most of the species are still living, some appear to be extinct. The travertine deposits of Geilston, near Hobart, Tasmania contain Helix geilstonensis and H. stanleyana, the latter still living. The calcareous Helix sandstone of the islands in Bass Strait are largely composed of shells of that genus and generally represent consolidated sand-dunes which have undergone a certain amount of elevation. One of the prevalent species is Helix simsoniana (Fig. 104 F), a handsome keeled form, somewhat related to the living H. launcestonensis. It is found in some abundance in the Kent’s Group and in the adjacent islands.

The large ovoid land-shells, Panda atomata, although still existing, are found associated with extinct marsupials, as Thylacoleo, in the stalagmitic floor of the Buchan Caves, Gippsland.

The Diprotodon-breccias of Queensland have afforded several species of Helix and other land-shells, as well as the brackish-water genus Melania. The Raised Beaches of Queensland, New South Wales, Victoria, and Tasmania all contain species of land and freshwater shells identical with those now found living in the same localities.

The Raised Beaches of New Zealand contain numerous marine shells all having living representatives. Some of these elevated beaches occur as high as 150 feet above sea-level at Taranaki, and at 200 feet near Cape Palliser in Cook Strait.

Many species of Pleistocene Mollusca identical with those now living in Torres Strait, the China Sea and the Philippine Islands are found in Papua. They occur in the greenish sandy clay of the hills near the present coast line and comprise the following genera of Gasteropods:—Ranella, Nassa, Mitra, Oliva, Terebra, Conus, Strombus, Bulla and Atys.

Characters of Cephalopoda.—

The highest class of the mollusca is the CEPHALOPODA (“head-feet”). In these shell-fish the extremity of the body or foot is modified, and furnished with eyes, a funnel and tentacles. It has also strong horny beaks or jaws which make it a formidable enemy to the surrounding life in the sea. In the chambered forms of this group the animal partitions off its shell at regular intervals, like the Pearly Nautilus and the Ammonite, inhabiting only the last chamber cavity, but still communicating with the earlier series by a continuous spiral tube (siphuncle). In some forms like the living squid and the extinct Belemnite, the shell is internal and either spoon-shaped, or dart-shaped, that is, subcylindrical and pointed.

Characters of Cephalopod Shells.—Nautiloidea.—

In geological times the nautiloid forms were the first to appear (in the Ordovician), and they were either straight shells, as Orthoceras, or only slightly curved, as Cyrtoceras. Later on they became more closely coiled, and as they were thus less likely to be damaged, they gradually replaced the straight forms.

The Ammonites have the siphuncle close to the outside of the shell, whilst in the Nautilus it is more or less median. The sutures or edges of the septa in Nautilus and its allies are curved or wavy, but not so sharply flexed or foliaceous as in Ammonites. The Nautiloidea range from the Ordovician and are still found living.

Ammonoidea.—

The Ammonoidea appear in Devonian times and die out in the Cretaceous. They were very abundant in Jurassic times, especially in Europe.

Belemnoidea.—

The Belemnoidea, ranging from the Trias to Eocene, comprise the extinct Belemnites, the interesting genus Spirulirostra of Miocene times, and the living Spirula.

Sepioidea.—

The Sepioidea or true Cuttle-fishes (“pen-and-ink fish”) range from the Trias to the present day.

Octopoda.—

The Octopoda, with Octopus and Argonauta (the paper “Nautilus”) are present-day modifications. The male of the latter is without a shell, the female only being provided with a delicate boat-shaped shell secreted by the mantle and the two fin-like expansions of the dorsal arms.

Ordovician Cephalopods.—

The Ordovician cephalopods of Australasia are not numerous, and are, so far as known, practically restricted to the limestones of the Larapintine series at Laurie’s Creek and Tempe Downs, in Central South Australia. Amongst them may be mentioned Endoceras warburtoni (Fig. 105 A), (a straight form in which the siphuncle is partially filled with organic deposits); Orthoceras gossei; O. ibiciforme; Trochoceras reticostatum (a coiled form); and Actinoceras tatei (a genus characterised by swollen siphuncular beads between the septa).