MUSEUM OF COMPARATIVE ZOOLOGY. 20% 
variety is evidently a more southern form and looks specifically distinct, but 
having only a few separate valves it seems better to wait for more material, 
which may prove more nearly intermediate, If distinct, it may be called 
L. lata. 
Famity SPONDYLIDA. 
Genus SPONDYLUS Lrynet. 
Spondylus Gussoni Costa. 
Spondylus Gussoni Costa, Cat. Sist., p. xlii, 1829; Phil., Moll. Sicil., I. p. 87, pl. v. 
f. 16, 1836. 
Found at Station 150, near Nevis, in 375 fms. ; at Station 193, in 169 fms. ; 
at Station 278, Barbados, in 69 fms.; at Station 262, Grenada, in 92 fms.; and 
in 640 fms., Yucatan Strait. 
The specimens have been compared with authentic European examples, and 
agree precisely. 
Genus PLICATULA Lamarck. 
Plicatula spondyloidea Mevuscuen. 
Ostrea spondyloidea Meuschen, Mus. Gronovianum, 1778. 
Plicatula ramosa Lamarck, An. s. Vert., ed. i., VI. p. 184, 1819. 
P. marginata Say, Journ. Acad. Nat. Sci. Phil., IV. p. 186, pl. ix. f. 4. 
Found in 36 fms. at Station 12; in 54 fms. off Sombrero Island; and in 
640 fms. in Yucatan Strait; in the last case probably ejected by a fish. 
This extremely variable shell has been erected into a number of species. It 
varies from nearly smooth to strongly plicate; from greenish white to closely 
streaked with brown. The young are rather pretty, the old ones coarse and 
rude. The number of ribs is most numerous when the shell is attached to a 
flattish surface; the ribs are fewest and most coarse when the shells grow on 
one another like reef oysters. 
Famity DIMYID. 
Genus DIMYA Rovatttr. 
Dimya Rouault, Mém. Soc. Géologique de France, 2me sér., III. p. 471, 1848. 
Stoliczka, Cret. Pelec. of S. India, Pal. Indica, IIL., ser. vi., pp. xxii, 897, 1871; 
(Aviculide, subfamily Vulselline). Dall, Science, Feb. 16, 1883, p. 51. 
Woodward, Man. Moll., 2d ed. by Tate, p. 408 (Ostreide), 1871. 
Margariona (Dall, Ms. 1882), Kobelt, Nachr. Mal. Ges., p. 186, 1882. 
Type Dimya Deshayesiana Rouault. 
