Manchester Memoirs, Vol. xlii. (1898), No. 4. 31 



Basterotia ARCULA, sp. nov. 

 (PL 2, f. 16.) 



B. testa cequivalvi^ inceqidlaterali^ subquadrata, inflata^ 

 valvis parurn hiulcis^ umbonibus incurvis, prQininulis^ mar- 

 gine dors all iitrimque recto ^ antico rotundato- truncate^ 

 postico oblique prodiicto^ ab umbonibus usque ad marginem 

 ventralem posteriorem carinato et acutangulato^ cardine in 

 utraque valva uno dente instructor dentibus productis^ 

 magnis, superficie sordide alba, granulosa, latere postico 

 cordifomni^plano-marginato, minute granuloso, tutus alba. 



Alt. 8, lat. 13, diam. 7-50 mm. sp. maj. 



Hab. Karachi, 3 fathoms, mud and sand. 



This genus, formerly known as Eucharis Recluz non 

 Latreille, bears, until the hinge with its conspicuous teeth, 

 one in each valve, be examined, a considerable resem- 

 blance to certain members of the family Arcadce. The 

 new species now before us, especially so; indeed, it might 

 be considered a small variety o{ Area tetragona L. 



The shell is equivalve, inequilateral, squarrose, inflated, 

 the valves hardly gaping laterally, the umbones incurved, 

 prominent, the dorsal margin straight on both sides of the 

 umbones, anteriorly the shell is roundly truncate, pos- 

 teriorly obliquely produced, from the umbones to the 

 posterior end of the ventral margin runs an acutely 

 angled keel, the surface of the shell is dirty white, 

 granulose, the posterior side flattened, plane margined 

 (with the keels just mentioned), heart shaped, minutely 

 granular. Within the shell is while. 



One perfect shell, and a larger half valve. 



{arcula, a little ark or chest.) 



Circe nana, sp. jtov. 

 (PL 2, f 9.) 



C. testa parva, oblique orbicularis solidiuscula, umbonibus 

 paullum attenuatis, prominulis, antic^ ovata, postice obtus- 

 angulo-truricatula, margine ventrali convexiusculo, dorsaliter 



