REPORT ON THE LAMELLIBRANCHIATA. Ill 



iuterrupted radiating opaque white lines which are visible to the naked eye. The 

 sculpture consists of verj^ thin narrow concentric lamellse, and extremely fine interA'ening 

 concentric striae, whicli, liowever, are only to be seen with the aid of a compound 

 microscope. The umbones are k little prominent, and in the three valves under 

 examination worn away at the extreme apex. The dorsal margin is somewhat oblique on 

 botli sides, a little arcuate in front, but rather straighter behind. The lower outline is 

 well curved, exhibiting only the faintest indication of a posterior sinuation. The hinder 

 cardinal tooth of the right valve is deeply cleft, and the lateral teeth are well developed, 

 the anterior being rather nearer the apex than the posterior. The internal ligament is 

 small, narrow, and located obliquely against the hinder cardinal tooth of the left valve, 

 in the right being separated from the posterior tooth by a narrow pit which receives the 

 corresponding tooth of the other valve. The muscular scars and pallial sinus are very 

 indistinct, as is often the case in thin shells. 



Length 9 mm., height 7-|, diameter 4^. 



Habitat. — Station 188, south of New Guinea, at a depth of 28 fathoms ; green mud. 



The valves here described are not probably full grown, but are sufficiently peculiar to 

 warrant their description. 



Tellina ( ?) semen, Hanley. 



Tellina semen, Hanley, Proc. Zool. Soc. Lond., 1844, p. 164. 

 Tellina semen, Hanley, in Sowerby's Thesaurus, vol. i. p. 249, pi. Ivi. fig. S. 

 Tellina semen, Eomer, Conch. -Cab., ed. 2, p. 9.5 {non Tellina semen, Sowerhy, Conch. Icon., 

 vol. xvii. fig. 232). 



Habitat. — Flinders Passage, in 7 fathoms, and Station 187, near Cape York, Torres 

 Strait, in fi fathoms ; also Levuka, Fiji Islands, at a depth of 12 fathoms. 



The locality of this species has not, I believe, been hitherto recorded. Tellina. 

 semitorta, Sowerby, is closely allied, being very similarly sculptured, but of a rather more 

 elongate form. The shell figured by Sowerby as Tellina semen is, on the contrary, too 

 short and too high for the present species. Both of these forms have a small internal 

 ligament immediately beneath the umbones, showing an approach to the genus Semele. 



Tellina ( ?) semitorta, Sowerby. 



Tellina semitorta, Sowerby, Conch. Icon., vol. xvii. figs. 221, a, h. 

 Habitat. — Port Jackson, Sydney, in 2 to 10 fathoms. 



This species is elongate, rather Donaciform, very inequilateral, moderately convex, 

 equivalve, white, marked with very fine irregularly radiating, interrupted and wrinkly 

 pellucid lines which are invisible to the naked eye. The front dorsal margin is very long, 

 only slightly sloping and almost rectilinear. The posterior is only about half as long, 



