210 



This curious little shell was also collected by the Exploring Expe- 

 dition, probably at the Cape de Verds. No hairy epidermal processes 

 appear on any of the specimens ; yet I cannot doubt that it belongs 

 to the genus where I have placed it. [Genus Fossarus.] 



Aplysia fimbriata. A species somewhat resembling A. dacty- 

 lorra la from South America was collected and figured by Dr. Perkins, 

 without, however, giving the colors. It is about five inches long 

 when fully extended, and about three and a half inches across the 

 lobes when quite expanded. The margin of the foot is somewhat 

 corrugated, and the margin of the lobes sinuate. There are eight or 

 ten large, black annuli on each side of the exterior of the mantle. 

 The margin of the interior, which is dark, is digitate with white, the 

 digitations being more or less rectangular. The cervical tentacles 

 are small and slender ; the cephalic tentacles have a coarsely fringed 

 margin. The calcareous shield is thin and delicate, with a strong 

 epidermis extending beyond its edge ; it is obliquely ovate-triangular, 

 quite acute at apex. 



Bulimus interstinctus, proves to be very variable in form, and 

 especially in color, being green, brown, ochreous, sometimes spotted, 

 &c. Bulimus rubicundulus, Nob. is one of these varieties. 



Q^= Vol. iv. 87, November, 1851. 



Pholas [Parapholas] ovoidea. T. ovoidea, solidula, cinerea, 

 postice hiantissima et epidermide valde vegata; margine ventrali 

 antiee lamina calcarea clauso ; apicibus ad trientem anteriorem testae 

 positis ; valvis sulco mediano partitis, portione antico rotundato 

 laminis concentricis radiatim striatis exasperato, portione postico sub- 

 cylindrico, striis concentricis remotis notato ; apophysi cardinali sub- 

 ulato, ad apicem dilatato ; valvis auxiliariis nullis ? 



Long. 3 ; lat. 1| ; alt. 2 poll. Inhabits Monterey. Maj. Rich. 



Remarkable for its short and ovoid form, and its great dehiscence. 

 The epidermis is prolonged posteriorly, much as in specimens of Mya 

 truncata. There seem to be no accessory pieces at the hinge, though 

 the hinge margin is reflected into a broad plate on each side so as to 

 answer the same end. 



Petricola bulbosa [is P. robusta, Sowb.]. 



Mactra nasuta. T. solida, transversa, ovato-cuneata, albida 

 epidermide straminea postice incrassata et fuseata induta ; vertice 

 fere mediano, acuto ; latere antico angustato, compresso, subadscen- 

 dente ; latere postico dilatato, truncato, hiante ; area dorsali postica 

 lanceolata, excavata : intus polita, Candida ; fovea ligamentali per- 

 obliquii ; dente V-formi tenui, elongato ; dentibus lateralibus crassis. 



