802 MESSRS. MELVILL AND SrANDE>^ ON [Nov. 13, 



menti llrls solibin ornata, ligavieiito Uiieari, marglne miimte 

 crenulato. 

 Alt. 5, lat. 3, diam. 2*75 mm. 



Hah. Persian Gulf. Lat. 24° 58' N., long. 56° 54' E. ; 156 

 fathoms, sliell-sand. 



Many half -valves of a small, narrowly I'homboid Modiolaria, 

 benving the characteristic generic sculpture. The ligament is 

 linear and marginal, no tooth visible, and the interior margin is 

 minutely crenulate. All our specimens are of much the same size, 

 and we deem them adult. 



Modiolaria cumingiana Dkr. 



I. Karachi. Fi-om 3 to 7 fathoms, amongst growth of sponges, 

 <fec. Extends in range to South Australia. 



LiTHODOMUS ATTENUATUS Desh. 



P.G. Locality not precisely specified. 



I. Karachi. Fovmd on rocks off Beach Forfc, Manora. 



LiTHODOMUS CINNAMOMEUS Lam. 



I. Karachi, not plentiful. 



LiTHODOMUS MALACCANus Reeve. 



I. Karachi. A little doubt attends this identification, the 

 specimens having been mislaid. 



LiTHODOMUS TowNSENDi, sp. n. (Plate LV. fig. 8.) 



L. testajxorva, cylindracea, tenui, epidermide nigro-brunnea, sitper- 

 ficie fere Iceingata, antics paulluhmi ragidosa, postice globosa, 

 extremitate antice prodacta, multum attenuata, fere caiidata. 



Alt. 7, lat. 18, diam. 5 mm. 



Hah. Persian Gulf : Gulf of Oman, on rocky ground. Lat. 

 27° N., long. 52= E. 40 fathoms. 



This little species, resembling a miniature L. caudigerus Lamk., 

 an inhabitant of the West Indies, or attenuatus Desh., from Chile, 

 differs from its congeners not only in size, but in the almost 

 complete absence of the wrinkled anterior surface, sometimes 

 channelled and shagreened, so usual in members of this genus. 

 We consider it full-grown. Two examples, exactly matching each 

 other, have as yet only occurred. It is a pleasure to associate 

 with this the name of Mi-. F. W. Townsend. 



Order III. PSEUDOLAMELLIBRANCHIATA. 



Fam. AvicuLiD^E. 



AvicuLA MACROrTERA Lam. { — Pteria Scop.) 



P.G. Maskat. 15 fathoms. 



Called " Mussel " or " Bombay Mussel." 



