Bay of Bengal and the Arabian Sea. 261 



consi(lcra1)ly larger and more solid shells, but af^rec in other 

 respects. The largest is 23 ram. long, 20 in height, and 15 

 in diameter. The specimens from Station 214 are smaller 

 and shorter than those from Station 341 : length 1G*5 mm., 

 height IG, diameter 12"25. 



Vesicomya cretacea, sp. n. 



Testa ovalis, valde inaequilateralis, mediocriter convexa, antice late 

 rotundata, postice magis acuta, alba, cretacea, periostraco tenuis- 

 sirao sordide flavesceute hie illic induta, striis incrementi sub- 

 rugose sculpta ; hniula eloiigata, cordiformis, linea impressa 

 circumscripta; area ligamenti elougata, profunda, utrinque 

 carinata ; valvoe mediocriter crassae, iiitus alb;© ; cicatrix antica 

 elougata, lajvis, postica latior; linea pallii lata, laivis, baud 

 sinuata ; dentes cardiuis duo in utraquc valva, illis valva) sinistra; 

 conjunctis, divergentibus. 



Longit. 57 mm., alt. 40, diam. 25. 



Hab. Station 327, W. of Burmah, 419 fath. ; Station 318, 

 ofFW. of Ceylon, 1085 fath. 



Beneath the ligament there is in each valve a rather deep 

 groove, "which starts a little behind the umbo and extends 

 backwards about 8 mm., becoming gradually broader. It 

 does not, however, appear to be for the reception of a 

 resilium, the ligament being distinctly external. 



More inequilateral than V. lepta, Dall, from California, 

 with the posterior dorsal margin more curved, the anterior 

 more descending, and the hinge rather stronger. 



The specimens fi'om Station 318, the largest of which is 

 only 44 mm. in length, and perhaps not adult, are thinner 

 than the unique type, with a less strong hinge and only a 

 faint indication of the groove in the nymphae described 

 above. 



Vesicomya bi'evis, sp. n. 



Testa brevis, subquadrata, multum convexa, valde inrequilateralis, 

 utrinque late rotundata, postice supra subaugulata, striis incre- 

 menti aspere sculpta, rufescenti-albida ; valvar baud crass?e, infra 

 marginem dorsi posticum sulco lato, hand profundo et parum con- 

 spicuo instructae, iutus albte, radiatim obscure striatse ; lunula 

 cordiformis, linea impressa circumdata ; area dorsalis posterior 

 profunda, lata, utrinque carinata ; dentes duo in utraque valva, 

 illis valvoe sinistroe conjunctis, antico valvae dextrse erecto, postico 

 irregulari. 



Longit. 36 mm., alt. 30, diam. 22. 



Hab. Station 259, W. of Malabar coast, 295-360 fath., 

 green mud and sand. 



Ann. & Mag. N. Hist. Ser. 7. Vol. xviii. 19 



