Encrusting Cyclostomata.
| 63. | brace |
Colony erect. Branches of two or one series of zooecia, divided at intervals by chitinous joints. Ovicells pear-shaped. Crisia (Fig. 237) |
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| 64. | brace |
Colony more or less circular, discoidal or cup-shaped, sometimes forming secondary colonies by marginal budding |
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| 65. | brace |
Zooecia separated by calcified interspaces, which may contain large pores, often difficult to distinguish from the orifices |
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No large pores as above. Orifices not spiny. Zooecia nearly always contiguous, except where an ovicell is developed |
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| 66. | brace |
Colony composed of one or more convex discs, bearing radial ridges, each composed of many zooecia Domopora |
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Colony encircled by a thin calcareous lamina, which gives rise to new zooecia, its centre usually devoid of zooecia when adult, and often bearing the orifice(s) of the ovicell. Zooecial orifices often spiny. Lichenopora |
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| 67. | brace |
Zooecia with a long, tubular, free portion, in some cases curved in a horizontal plane. Colony fan-shaped until a late stage. Tubulipora flabellaris |
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Tubular portion absent, or for the most part curved in a vertical plane. Some of the orifices may be closed by a calcareous plate. Colony circular or bluntly lobed Diastopora |
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| 68. | brace |
Zooecia in one or few series, forming a linear or branched colony, which is closely adherent, but may give rise to short erect portions. Branches narrow, but often broadening at their ends. Zooecia usually with a free upper end Stomatopora |
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Colony broadly lobed, some of the zooecia in transverse or oblique ridges composed of contiguous zooecia, arranged like a row of organ-pipes Idmonea serpens |
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Colony broadly lobed, or fan-shaped; zooecia in many series, which are not arranged like organ-pipes Tubulipora |
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| 69. | brace |
Well branched. Orifices confined to one surface of the colony |
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| 70. | brace |
Zooecia in transverse rows, their upper ends united in the manner of a row of organ-pipes. Ovicell (when present) an inflation of the front of the branch Idmonea atlantica |
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Zooecia not in regular transverse rows. Ovicell (when present) large, mostly on the back of the branch Hornera |
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| 71. | brace |
Branches cylindrical, their ends massive and raised into radial ridges, which carry the orifices Domopora stellata |
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Ends of zooecia tubular, arranged all round the branch. Entalophora |
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Encrusting Ctenostomata.
| 72. | brace |
Colony entirely adherent, or forming thick, soft, erect lobes |
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Colony erect, well-branched, dark and opaque, resembling seaweed. Zooecia with a long tubular free portion Anguinella palmata |
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| 73. | brace |
Orifice large, with two distinct lips. A variable number of stout, brown spines. Encrusting Flustrella hispida |
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Orifice small, rounded, borne by a more or less distinct papilla. Encrusting or erect. Zooecia crowded, rarely in single lines. Alcyonidium |
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Orifice small, rounded. Zooecia widely separated, connected by narrow tubes Arachnidium |
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| 74. | brace |
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| 75. | brace |
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| 76. | brace |
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Zooecia long, less regularly arranged. Polypide with a gizzard. Bowerbankia (Fig. 238) |
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| 77. | brace |
Clusters of zooecia very regular, occurring immediately below a bifurcation of the axis. Zooecium with a broad base, not movable. Amathia lendigera |
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Zooecia arranged like the pinnules of a leaf, with a constricted base, and movable on the branch Mimosella gracilis |
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| 78. | brace |
Main stem zigzag. Branchlets delicate, many ending in sharp points. Zooecia small, ovoid Vesicularia spinosa |
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Axis jointed. Zooecia small, in small clusters. Polypide without a gizzard Valkeria uva, var. cuscuta |
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Zooecia in whorls, attached to the axis by thread-like stalks, much longer than themselves Hippuraria egertoni |
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| 79. | brace |
Zooecia pear-shaped, produced at the lower end into a distinct stalk. Gizzard absent |
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Zooecia not distinctly stalked, although sometimes constricted at the base |
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| 80. | brace |
Stalk long. Zooecium movable on its stalk, compressed, with a membranous area on one side. Twelve or more tentacles. Usually found on Crustacea Triticella |
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Stalk variable. Zooecium very transparent; orifice bilabiate. Ten to sixteen tentacles Farrella repens |
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Zooecium very small, much elongated and narrow. Eight tentacles. Valkeria tremula |
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| 81. | brace |
Zooecia short, minute, with a few short spines on each side of its broadened base. Upper end tubular Buskia nitens |
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| 82. | brace |
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| 83. | brace |
Zooecia large (about 1⁄16 inch long), distant, constricted at the base, bearing scattered bristles. Usually found on Crabs or Hydroids. Avenella fusca |
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Zooecia tall, cylindrical, not constricted at the base. Cylindroecium |
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| 84. | brace |
Zooecia minute. Axis dilating at intervals into swellings, from which new zooecia originate. These may give rise to new stolons, or directly to new zooecia. No gizzard. Found in brackish or fresh water Victorella pavida |
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| 85. | brace |
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Zooecia long, scattered or in groups. Gizzard present. Bowerbankia (creeping forms) |
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It is highly probable that the Ctenostome genus Hypophorella[610] will before long be added to the British Fauna. The animal consists of delicate stolons, which give off small zooecia at intervals; and it is known to excavate passages in the substance of the tubes of certain Polychaet worms (Chaetopterus and Lanice).
ADDENDUM TO CHAETOGNATHA
Since the Chapter on the Chaetognatha was printed the following list[611] of "The Known Chaetognaths of American Waters" has appeared:—
1. Sagitta elegans Verr. This species resembles S. bipunctata (vide pp. 191 and 193), but differs in size, in the relative proportions of caudal and body segments, and in the presence of diverticula from the intestine.
2. Sagitta flaccida Con. This species resembles S. hexaptera (vide p. 193); it is, however, smaller (length, 1.3-1.8 cm.) and has more spines (anterior, 7-8, posterior, 10-12), and its tail segment is relatively smaller.
3. Sagitta tenuis Con. Length, 5.25 mm.; hooks, 7-8; anterior spines, 4-5; posterior spines, 7-10.
4. Sagitta hispida[612] Con. Length, 7-11 mm.; hooks, 8-9; anterior spines, 4-5; posterior spines, 8-15; tail segment one-third body length; intestine with two diverticula; sensory hairs very numerous.
5. Sagitta hexaptera (vide p. 193).
6. Krohnia hamata (vide p. 194).
7. Spadella maxima Con. Length, 5.2 cm.; hooks, 6; anterior spines, 3-5; posterior spines, 5-7; epidermal thickenings round the neck.
8. Spadella draco (vide p. 194).
9. Spadella schizoptera[612] Con. An opaque, yellowish-brown species living among algae. Length, 4 mm.; hooks, 8; anterior spines, 4-6; posterior spines wanting. Caudal segment occupies one-half the body length.
Professor Verrill states that the name S. gracilis (vide p. 191) was due to a clerical error, the species really referred to being S. elegans.
A. E. S.
Every reference is to the page: words in italics are names of genera or species; figures in italics indicate that the reference relates to systematic position; figures in thick type refer to an illustration; f. = and in following page or pages; n. = note.