FOOTNOTES:

[126]Three very interesting bivalve shells, distinct, it appears, from the other species of the genera to which they respectively belong, have been discovered in the above-mentioned river by Major Denham. The first, a species of Ætheria, I distinguish as

Ætheria Denhami: testa irregulariter rotundato-oblonga, ad cardinem gibbosa, utriusque valvæ callo cardinali basim versus oblique truncato.

Hab. in Africæ interioris fluvio Gammaroo.

The form of the cardinal callosity to which the semi-internal ligament is attached affords a distinction sufficiently characteristic of the species: its oblique truncating plane, which extends towards the rather indistinct umbo, is, in the closed state of the shell, in partial contact with that of the corresponding and similarly formed callus of the other valve. The general form of the shell is oblong or rounded, but appears to be subject to considerable variation: one of the specimens before me exhibits the exterior of Lamarck’s A. transversa, which latter is no doubt a casual variety only of the other species described and figured by that naturalist.

These shells are externally furnished with a blackish-brown epidermis; beneath this a white film is deposited, on the removal of which a beautiful pearly naker appears, similar to that of the internal surface of the valves. The blistered appearance of the interior of both the valves is constant in all specimens, and may, as intimately connected with the structure of the shell, be considered of sufficient importance to be admitted into the distinctive character of the genus.

Lamarck, imagining that these shells live at the bottom of the sea, named the genus, as he says, after one of the daughters of Oceanus. Though the Ætheriæ are now well known to be fluviatile shells, the emendators of zoological nomenclature may still be exonerated from framing a new name for this genus, since the old one is derivable from the original locality of its species; a part of central Africa having, according to Pliny, been anciently known by the appellation of Ætheria.

The second shell, a new species of Iridina, may be thus characterized:

Iridina Oudnæi: testa transversa ovato-lanceolata tumidiuscula, cardine stricto sub-edentulo, basis margine sinuato.

Hab. cum priore.

This species is very distinct from E. elongata in form and in the hinge line being without crenulation; and from E. nilotica, which it resembles in the latter of those characters, it differs by its form, inferior thickness, and iridescence. The length of the specimen before me is 4⅔, its greatest breadth at the umbo nearly two inches. Placed on the basal edge, which is concave, the anterior side presents a considerable slope from the umbo to the exterior margin, which gives the valves a tapering or ovate-lanceolate form. The external epidermis, of a greenish-brown colour, exhibits slightly undulating striæ of growth. The interior surface is slightly uneven-undulated, white, with delicate opalescent colours, green and faint pink; the former chiefly disposed in spots. The muscular impressions are more slightly marked than in the other species.

For the third shell, which I considered as a new species of Anodon, I propose the name of

Anodon Clappertoni: testa transversim oblonga, antice in extremo cardine acute excisa.

Hab. cum antecedentibus.

The notch at the anterior extremity of the hinge being always acute, never obtusangular or rounded, I have confined myself to it in the distinctive character of this species, which differs in several other respects from Anodon purpureus and rugosus of Swainson, to both of which it is, however, nearly related. The size of the shell, in the several specimens before me, varies from 1½ by ¾ of an inch to 3 inches by nearly 1½. Its form is transverse-oval, with a slight slope at the anterior end. The hinge margin is straight. Epidermis olive-green, appearing of a reddish-brown colour, owing to the pink colour of the surface underneath, which latter in one specimen passes into bluish-green at the umbones. Muscular impressions three; one of them, at the anterior end, oval, and continued in a faint tapering form towards the hollow of the umbo; of the two other impressions, which are both stronger marked, the one nearest to the edge of the valve is oval, with a small rounded sinus at the inner border, and close to it a smaller irregularly oval mark with notched margin: the two principal marks are connected by the edge of the impression of the mantle, the smaller mark being placed within the line. The tinge of the internal surface is pink, imperfectly painted over as it were with white. The several specimens, in different stages of growth, exhibit all these characters; there is, however, among them a single valve of rather larger dimensions and more rounded than the rest, with a fine bronze-coloured internal surface like that of Iridina nilotica. Whether this is to be considered as a distinct species, or only as a variety indicative of the full grown state of the shell, I must leave to the decision of conchologists more experienced in discriminating the ambiguous species of this genus.

No. XXIV.

Thermometrical Journal kept at Kouka in Bornou.

Date. Winds. Fah. Thermometer.
6 a.m. Noon. 3 p.m.
March 1823.
15 E.N.E. 70 98 103
Sunday, 16 S.S.E. 75 95 102
17 S.S.E. 78 99 104
18 E.N.E. 77 104
19 S.E. 98
20 E.N.E. 78 95 101
21 N.E. 82 100 105
22 E.N.E. 80 97 100
Sunday, 23 N.E. 78 90 94
24 N.E. 79 94 97
25 E.N.E. 79 97 101
26 E.N.E. 79 100 103
27 E.N.E. 79 101 103
28 E.N.E. 82 97 98
29 E.N.E. 80 97 100
Sunday, 30 N.E. 80 94 97
31 E.N.E. 80 94 96
April.
1 N.E. 77 98 101
2 N.E. 80 95 100
3 S.E. 80 99 101
7 N.E. 80 99 102
8 N.E. 80 99 103
9 E.N.E. 78 98 102
10 E.N.E. 77 97 99
11 N.E. 72 100 100
12 N.E. 78 104 107
Sunday, 13 N.E. 84 100 105
14 E.N.E. 82 100 105
15 N.E. 87 103 105
16 E.N.E. 86 95 105
17 E.N.E. 87 99 106
18 E.N.E. 86 103 109
19 N.E. 88 102 106
Sunday, 20 E.N.E. 87 102 107
21 E.N.E. 85 100 100
22 E.N.E. 86 102 103
23 E.N.E. 85 102 103
24 N.E. 83 101 103
25 E.N.E. 85 103 102
26 N.E. 85 103 103
Sunday, 27 N.E. 86 102 102
28 N.E. 83 101 103
29 E.N.E. 81 103 103
30 E.N.E. 82 103 103
May.
1 E.N.E. 85 106 106
2 N.E. 85 103 105
3 N.E. 83 105 98
Sunday, 4 E.N.E. 81 99 99
5 E.N.E. 82 95 96
6 E.N.E. 81 102 102
7 N. 86 104 103
8 N.E. 71 99 96
9 N.E. 81 99 96
10 N.E. 85 95 94
Sunday, 11 N.E. 86 101 95
12 Calm. 81 99 95
13 W.S.W. 75 98 98
14 W.S.W. 75 95 98
15 W.S.W. 74 97 97
16 W.S.W. 72 92 95
17 S.W. 74 97 98
Sunday, 18 W.S.W. 74 96 99
19 W.S.W. 73 96 99
20 W.S.W. 76 95 99
21 W.S.W. 74 102 100
22 W.S.W. 73 100 100
23 W.S.W. 84 104 101
24 S.W. 76 96 96
Sunday, 25 S.W. 73 96 96
26 S.W. 81 98 100
27 S.W. 76 99 100
28 S.W. 80 98 99
29 W.S.W. 81 97 102
30 W.S.W. 82 100 102
31 W.S.W. 80 100 102
June.
Sunday, 1 W.S.W. 76 97 97
2 W.S.W. 80 97 96
3 W.S.W. 81 99 99
4 W.S.W. 81 99 100
5 W.S.W. 80 99 100
6 S.W. 80 98 98
7 S.W. 75 95 100
Sunday, 8 S.W. 78 98 98
9 S.W. 79 95 97
10 S.W. 78 89 90
11 W.S.W. 75 89 93
12 W.S.W. 79 87 95
13 W.S.W. 80 95 95
14 W.S.W. 81 97 97
Sunday, 15 W.S.W. 82 99 97
16 W.S.W. 81 97 96
17 W.S.W. 81 99 101
18 W.S.W. 80 97 99
19 W.S.W. 79 89 93
20 W.S.W. 78 92 93
21 W.S.W. 77 92 95
Sunday, 22 W.S.W. 78 98 99
23 S.W. 81 95 87
24 S.W. 76 95 87
25 S.W. 80 97 96
26 S.W. 81 94 95
27 S.W. 87 96 98
28 S.W. 81 97 92
Sunday, 29 S.W. 82 96 97
30 S.W.
July. 1 S.W. 82 97 99
2 S.W. 81 92 92
3 S.W. 82 93 94
4 S.W. 74 85 84
5 S.W. 78 89 94
Sunday, 6 S.W. 78 89 96
7 S.W. 78 89 91
8 S.W. 78 90 92
9 W.S.W. 81 87 92
10 W.S.W. 77 92 95
11 W.S.W. 75 85 97
12 S.W. 75 85 88
Sunday, 13 S.W. 71 79 82
14 S.W. 72 82 89
15 S.W. 75 83 90
16 S.W. 76 87 90
17 S.W. 72 84 93
18 S.W. 76 83 89
19 S.W. 75 86 90
Sunday, 20 S.W. 74 87 89
21 S.W. 72 83 86
22 S.W. 73 84 87
23 S.W. 73 86 89
24 S.W. 74 84 90
25 S.W. 73 83 87
26 S.W. 71 84 86
Sunday, 27 S.W. 80 86 89
28 S.W. 76 86 90
29 S.W. 73 84 87
30 S.W. 76 85 95
31 W. 76 85 92

Date. State of Weather. Fah. Thermometer.
6 a.m. Noon. 3 p.m.
1823.
Aug. 1 Rain all night. 75 82 86
2 73 78 79
3 Sunday. Rain in evening. 74 80 82
4 78 82 83
5 76 82 84
6 Rain much. 73 77 78
7 74 78 81
8 Rain. 76 80 81
9 75 81 82
10 Sunday. Rain, loud thunder. 74 77 80
11 76 81 83
12 Rain and thunder all night. 79 83 85
13 75 80 81
14 76 80 85
15 Rain, thunder, vivid lightning. 77 84 87
16 76 82 85
17 Sunday. 78 83 85
18 77 84 86
19 Rain and thunder during the night. 79 85 86
20 Rainy day. 78 84 85
21 75 82 83
22 Much rain. 74 79 83
23 Morning cloudy. 74 80 84
24 Sunday. Drizzling rain. 76 83 85
25 Night violent. 75 77 79
26 Night. 75 78 79
27 All night. 74 78 79
28 Day and night, showers. 73 77 79
29 Rain. 74 78 80
30 75 80 82
31 Sunday. Rain, much thunder. 74 78 80
Sep. 1 74 79 81
2 76 84 86
3 79 85 89
4 80 85 88
5 Morning. Rain and thunder. 80 80 81
6 78 83 84
7 Sunday. 78 85 86
8 Rain. 79 80 81
9 78 83 85
10 Night, hurricane, east. 80 86 88
11 South. 78 85 87
12 80 86 88
13 79 85 87
14 Sunday. 78 86 89
15 80 86 89
16 81 87 89
17 Cloudy afternoon. 81 88 89
18 80 85 87
19 Hurricane, east and a half south. Strong 3 p.m. 80 87 85
20 80 84 87
21 Sunday. 78 85 87
22 79 87 89
23 78 86 88
24 80 88 90
25 82 89 92
26 Violent storm, noon wind N. hail and rain. 80 89 90
27 76 86 89
28 Sunday. 80 86 88
29 81 87 91
30 80 86 91
Oct. 1 Rain and wind in night. 80 87 91
2 78 84 85
3 80 85 88
4 Wind, thunder. 81 87 90
5 Sunday, rain and wind. 80 86 88
6 79 87 89
7 80 88 90
8 80 89 93
9 79 89 92
10 Breeze N.W. 78 89 91
11 77 90 92
12 Sunday, 79 92 94
13 78 92 94
14 79 91 93
15 77 92 93
16 83 92 94
17 81 92 94
18 80 90 93
19 Sunday, 81 92 94
20 79 92 94
21 80 92 94
22 81 93 95
23 75 90 92
24 76 85 88
25 77 87 90
26 Sunday, 77 88 91
27 78 90 92
28 78 90 91
29 79 91 93
30 78 88 90
31 79 89 92
Nov. 1 78 87 90
2 Sunday, 76 89 91
3 75 88 89
4 76 88 90
5 77 87 89
6 77 88 90
7 76 87 90
8 75 86 88
9 Sunday, 76 88 90
10 77 86 89
11 79 87 88
12 76 88 90
13 74 87 89
14 74 86 88
15 73 87 89
16 Sunday, 74 88 89
17 74 83 86
18 75 85 87
19 75 86 88
20 75 85 87
21 75 86 88
22 69 78 81
23 Sunday, 71 79 81
24 69 77 79
25 68 78 80
26 67 79 81
27 66 78 80
28 65 77 79
29 66 77 79
30 Sunday, 67 79 80
Dec. 1 66 79 81
2 67 78 80
3 66 79 81
4 65 78 80
5 67 80 82
6 68 80 82
7 Sunday, 68 78 80
8 63 76 78
9 64 76 78
10 63 75 77
11 64 76 78
12 64 77 78
13 64 78 78
14 Sunday, 63 75 77
15 ⎧
⎪
⎪
⎨
⎪
⎪
⎩		 Dull cold days. Wind N.N.E. and E., but a cloudy sun at noon. ⎫
⎪
⎪
⎬
⎪
⎪
⎭		 64 74 76
16 63 75 77
17 64 75 76
18 63 74 76
19 63 72 74
20 63 71 72
21 Sunday, 64 73 75
22 65 74 75
23 66 73 75
24 65 74 76
25 66 74 77
26 64 75 76
27 64 72 74
28 Sunday, 65 73 75
29 64 74 76
30 N.E. cold. 61 63 65
31 58 66 73
1824.
Jan. 1 61 74 76
2 60 71 72
3 61 72 73
4 Sunday, 60 70 74
5 61 73 75
6 63 75 77
7 65 77 79
8 65 82 84
9 66 84 86
10 65 83 85
11 Sunday, 64 82 84
12 65 83 85
13 66 84 86
14 66 85 86
15 Elephant, 70 85 87
16 75 86 87
17 74 85 86
18 Sunday, 75 87 89
19 75 90 91
20 74 87 89
21 75 88 90
22 74 86 87
Mar. 2 80 94 96
3 77 94 95
4 78 95 97
5 78 95 96
6 80 95 97
7 Sunday, 79 96 98
8 80 95 96
9 79 91 93
10 79 92 94
11 78 93 95
12 79 92 94
13 78 94 96
14 Sunday, 80 95 97
15 82 95 98
16 80 94 96
17 79 93 95
18 Winds south. 79 92 94
19 Heavy dull sky. 78 91 93
20 79 93 95
21 Sunday, 79 94 96
22 78 93 95
23 North breeze. 75 90 92
24 76 89 91
25 77 90 91
26 78 94 97
27 80 95 99
28 Sunday, 83 99 101
29 85 99 102
30 84 98 100
31 85 99 100
Apr. 1 86 97 99
2 85 94 96
3 84 95 96
4 Sunday, 79 93 95
5 84 96 100
6 86 99 101
7 87 98 100
8 Slight rain with lightning. 86 100 104
9 90 101 104
10 87 99 102
11 Sunday, 88 100 103
12 86 102 105
13 87 103 105
14 86 101 103
15 87 101 102
16 86 100 103
17 85 100 104
18 Sunday, 86 101 105
19 84 101 103
20 85 100 105
21 86 100 106
22 N.W. wind, 86 100 100
23 85 100 102
24 Thick atmosphere. 86 102 103
25 Sunday, 79 99 102
26 ⎫
⎬
⎭		 Violent N.W. winds. ⎧
⎨
⎩		 86 103 103
27 86 102 102
28 83 102 103
29 80 102 103
30 82 103 103
May 1 86 104 106
2 Dull and thick, with wind. 83 100 104
3 ⎫
⎪
⎬
⎪
⎭		 Rain, Thunder.
4 ⎰
⎱		 83 100 100
5 81 100 100
6
7 86 98 100
8 85 99 101
9 Sunday, 87 99 102
10 88 99 101
11 87 97 99
12 89 99 101
13 First day of summer. 88 99 106
14 80 99 104
15 81 100 104
16 Sunday, 86 100 104
17 84 99 100
18 86 100 102
19 87 101 103
20 88 102 104
21 86 100 104
22 85 99 104
23 Sunday, 86 98 104
24 ⎫
⎪
⎬
⎪
⎭		 Sun rises at 5. 10. and the day is 13h. 10m. sets 6. 10. ⎧
⎪
⎨
⎪
⎩		 88 101 102
25 87 100 103
26 88 100 104
27 87 101 103
28 88 102 103
29 Morning, thick hot vapours. 89 101 102
30 Sunday. Night stormy, no rain. 91 100 101
31 88 98 100
June 1 90 101 102
2 89 99 102
3 90 103 105
4 90 102 104
5 Dull. 89 103 104
6 Sunday, 88 102 103
7 87 101 102
8 88 99 100
9 89 100 102
10 87 98 99
11 87 97 100
12 Wind S.S.E. 89 99 102
13 Sunday, 88 100 104
14 89 100 104
15 90 101 103
July 19 80 87 90
20 78 87 89
21 Much rain. 79 88 90
22 Dull. 80 86 86
23 80 90 95
24 79 89 91
25 Sunday, 80 91 92
26 80 90 92
27 78 88 90
28 79 87 91
29 78 88 92
30 80 89 91
31 80 89 90
Aug. 1 Sunday, 81 92 96
2 81 93 95
3 80 90 91
4 78 87 90
5 79 89 92
6 Sultry. Aide kebir. 80 94 95
7 Night, rain. 81 91 93
8 Sunday, 78 84 87
9 79 88 90
10 80 89 90
11 79 88 90
12 Much rain. 80 89 90
13 78 80 82
14 79 81 83
15 Sunday, 76 82 81