Carboniferous Fossils from Siam. 117 



by Wheelton Hind/ but the ornamentation is finer. We may also 

 compare, as regards general shape, the Culm shell from Hagen, 

 figured by Nebe ^ as Macrodus cf . nornialis De Koninck. 



Edmondia sp. (PI. II, Fig. 6.) 



One internal cast and external impression of a small oval 

 shell measuring 10"5 mm. in length and 8"5 mm. in height has 

 the anterior and posterior ends subequally rounded ; the inferior 

 margin is strongly arched, and the beak is obtuse, broad, and less 

 than one-third the length of the shell from the anterior end. The 

 surface is covered with strong subangular, rather unequal rugse. 

 It seems comparable to Edmondia MacCoyi Wh. Hind,^ but has 

 not such blunt extremities. Mansuy ^ has described a species of 

 Edmondia from the Carboniferous of French Indo-China, but it 

 does not seem to be identical with our form. 



Allorisma (?) sp. 



One imperfect right valve of an elongated shell which has a 

 somewhat swollen and incurved beak and strong concentric rounded 

 undulations of subequal size, directed slightly obliquely to the length 

 of the shell, seems probably comparable with A. sidcata (Fleming).^ 

 The anterior end seems rather abruptly truncate, and the posterior 

 end rather sharply rounded ; there is a strong rounded umbonal 

 ridge running down to the latter end, with a very weak, wide 

 depression in front of it, crossing the shell to the inferior margin, 

 which is faintly sinuated. The length of the shell is about 24 mm., 

 and the height at the anterior end about 10 mm. Species of 

 Allorisma have been recorded from the Upper Carboniferous of 

 Sumatra." 



Protoschizodus (? ?) sp. 



The occurrence of a species of this genus is suggested by some 

 very imperfect casts too poor for precise identification. 



Posidonomya Becheri Bronn, var. nov. siamensis. (PL II, Fig. 7.) 



Shell obliquely suboval to subrhomboidal, posteriorly expanded 

 and flattened, with a long, gently curved or nearly straight hinge-line, 

 rather less than the length of the shell ; posterior margin gently and 

 continuously arched, meeting hinge-line at very obtuse angle ; 

 inferior margin more or less sharply rounded ; anterior margin nearly 

 straight, with weak, wide, shallow sinuation at base of long narrow 

 triangular ear ; hinge-line meeting anterior margin at about 75 



> Wheelton Hind, Wlon. Brit. Carb. LamelL, vol. i, p. 140, pi. x, figs. 16-19. 

 2 Nebe, Neues Jahrb. f. Miner. GeoL, Beil. Bd. xxxi, 1911, p. 458, t. xiv, 

 fig. 7. 



•* Wheelton Hind, Brit. Garb. Lamellibr., vol. i, p. 329, pi. xxxvi, figs. 23-30. 

 * Mansuy, op. cit., vol. ii, fasc. v, 1913, p. 25, pi. iv, fig. 6. 

 ^ Wheelton Hind, op. cit., p. 422, pi. xlviii, figs. 3-11. 

 ^ Fliegel, Palceontographica, Bd. xlviii, 1901, pp. 108-9. 



