1906.] MOLLUSKS FROM THE PERSIAN GULF, 793 



M.C. Lat. 25° 10' N., long. 60° 34' E. 40 fathoms, off Charbar; 

 abundant, but mostly half -valves, dead. Also in Charbar Bay at 

 15 fathoms. 



I. Karachi. 5 fathoms ; thin mud. 



Fam. SoLENOMYID^. 



SoLEXOMYA PATAGONicA E. A. Sm. [Solemyci.) 



P.C4. Gulf of Oman. Lat. 24° 49' N., long., 56° 56' E. ; 

 225 fathoms. 



The extension of i-ange now proved to exist for this comparatively 

 recently described species is peculiarly remarkable. Our specimens 

 have been submitted to the author, and pronounced identical with 

 the original gatherings off Patagonia. 



Order II. FILIBRANOHIATA. 



Suborder A. ANOMIACEA. 



Fam. AxoMiAD^. 



Anomia ach^lts Gray. 



I. Karachi. Parasitic on Placenta, various Pectmidcs, and 

 other Mollusca. 



Anomia (Enigma) ^nigmatica Anton. 



I. Karachi (il/cy or 5«^er). Not yet recorded by Mr. Townsend. 

 Bombay (^A bercromhie). 



Placenta orbicularis Betz. (= Placuna placenta L.). 



P.G. In many places : mostly on muddy banks at low water. 

 I. Karachi. Bombay, abundant (^4. Abercrombie, E. H. 

 Aitken and Captain A. J. Peile). Paiijim and Goa [Lt.-Col. H. D. 

 Olivier). 



Largely used, both in India and China, in the manufacture of 

 window panes, and is a general substitute for glass. It also 

 shelters a small crab, and seed pearls are not infrequent in the 

 species — very pi'obably on account of the crustacean causing 

 irritation. 



Suborder B. AECACEA. 



Fam. Arcad.e. 



Arc A BiSTRiGATA Dunker. 



I. Karachi: found on rocks at low tide. Bombay (Paetel, 

 Cat. iii. p. 211). Found there also by Mr. Abercrombie. 



Arca requiescens Melvill, sp. n. (Plate LIY. fig. 2.) 



A. testa minicta, anguste-trapezoidea, versus medium depressa, 

 incequilate7rdi, ceqioivalvi, postice magis expansa ; costis longi- 



53* 



