REPORT O.N THE LAMELLIBRANCHIATA. 279 



This species is not quite so elongate as the European JSIodioJaria marmorata of 

 Forbes, but corresponds in other respects, so that it is questionable whether it should not 

 take varietal rather than specific rank. 



Another species described bj^ Fischer under this name (Jouni. de Conch., vol. xxx. 

 p. 53) may be called Modiolaria Jischeri. It was dredged in the Bay of Biscay, at a 

 depth of 1160 metres. 



Modiolaria semigranata (Reeve). 



Liiliodoinus seiidgranatus. Reeve, January 1858, Conch, loon., vol. x. pi. v. figs. 28, a, h. 

 Modiola suhclavata, Libassi, Atti Accad. Sci. Palermo, 1859, vol. iii. p. 13, fig. 7. 



Habitat. — Station 70, w-est of the Azores, in 1675 fathoms (Challenger); Lanzerote 

 and Tenerife (M' Andrew). 



None of the specimens from this locality are as large as the fossil shells figured by 

 Libassi. In the living state they are more or less covered with a yellowish epidermis, 

 which is of a hirsute character on the posterior portion of the valves. They varj' con- 

 siderably in form, some being longer and narrower than others ; all, however, exhibit the 

 median sinuation at the ventral margin. The largest of them is only 5^ mm. in length, 

 but a specimen from Lanzerote presented to the Briti.sh Museum by the late R. M' Andrew, 

 Esq., exceeds that by 2 mm. 



Modiolarca, Gray. 



Modiolarca trapezina (Lamarck). 



Modiola trapesina, Lamarck, Anira. sans vert., ed. 2, vol. vii. p. 24. 



Modiola trapezina, Kiister, Conch. Cab., vol. viii. Heft. iii. pi. vi. figs. 16, 17. 



Modiolarca trapezina, Gray, Synopsis Brit. Mus., 1840, p. 151; Proc. Zool. Soc. Lond., 1847, 



p. 199. 

 Modiolarca trapezina, H. and A. Adams, Gen. Rec. Moll., vol. iii. pi. cxxii. 6gs. 1, \a. 

 Modiolarca trapezina, Cheuu, Man. de Conch., vol. ii. p. 156, fig. 777. 

 Pliaseolicama trapezina, Hup6, Gay's Hist. Chile, Malacologia, pi. viii. fig. 9. 

 Pliaseolicuma magellunica, Eousseau, Voy. au Pol. Sud. Moll., p. 116, pi. xxvi. figs. 2, a-d. 

 Gaimardia trapesina, Gould, Wilkes's United States Explor. £.\ped., pi. xli. fig. 568. 



Habitat. — Station 311; ofi" the coast of Patagonia, in 245 fathoms, a single dead 

 valve only. Station 315, off the east side of the Falkland Islands, Hving at a depth of 

 12 fathoms; also dead shells at Marion Island, south-east of the Cape of Good Hope, 

 in 50 to 100 fathoms; and finally in Royal Sound, Kerguelen Island, "on the surface," 

 no doubt attached to floating Algxe, and also dead, in 28 fathoms. 



The form of this species is somewhat variable, especially with regard to the anterior 

 end, some specimens (t'lVZe Gould's figure) having this part considerably narrower and 

 more prolonged than others. The hinge is generall)' composed of a single small 



