70 DR. BAIRD ON NEW SPECIES OF SHELLS. [Feb. 10, 



13. Lyonsia saxicola, Baird. 



L. testa ovato-oblonga, medio gibba, tenui, fragili, antice pro- 

 ducta, clausa, postice cotnpressiuscula, hiante; umbonibus magnisj 

 incurvis ; epidermide olivacea, striata ; margine dorsali recti- 

 usculo, margine ventrali Jlexuoso, hiante. 



The length of a moderate-sized specimen is about 3 inches, of a 

 large specimen 4| inches ; the breadth from the beaks to the ventral 

 margin is about 2 inches and 2| inches. 



Hab. Holes in rocks in Esquimalt Harbour, Vancouver Island. 

 {Mus. Brit.) 



This species is the largest of the genus that has yet been discovered. 

 It is of an ovate-oblong shape, gibbous in the centre, produced ante- 

 riorly, compressed posteriorly and gaping. The beaks are large and 

 incurved : it is covered with an olive-coloured epidermis, which is 

 striated transversely. The ventral margin is gaping and flexuous. 

 This species resembles considerably the L. navicula of Adams and 

 Reeve ('Zoology of the Voyage of the Samarang'), from the Sooloo 

 Sea, and might be taken for a very large specimen of it, and, indeed, 

 is considered to be so by Mr. Adams himself, who informed me he 

 had taken identically the same species, as to size, &c., from the seas 

 of Japan. Besides the size, habitat, and place of abode, this species 

 differs from L. navicula in the form of the anterior extremity of the 

 shell and the more gaping ventral margin. Owing to the pecuhar 

 place of abode (holes in the rocks), it varies considerably in size and 

 form ; but in all the specimens which I have seen, ten in number, it 

 does not vary in the produced anterior extremity. The striae seen 

 on the surface of the epidermis do not appear to extend from it to the 

 shell underneath. It lodges always, Mr. Lord says, in holes in the 

 Tocks, from which it is very difficult to extract it, without breaking 

 it ; for it would appear to take up its abode in a small hole, enlarging 

 it as it increases in size itself. The substance of the shell, without 

 being very thin, is exceedingly brittle ; and few specimens were 

 brought over without being cracked across in various places, appa- 

 rently in the act of drying. The ossicle covering the front of the in- 

 ternal cartilage is strong and well developed. 



14. Crassatella esquimalti, Baird. 



C. testaparva, cordato-trigona, crassiuscula, olivacea, transversim 

 undato-plicata, antice productp-rotundata, postice subtriincata, 

 margine ventrali rotundata, umbonibus prominulis, lunula longe 

 caudata. 



Long, rather more than § inch ; lat. nearly | inch. 



Hab. Esquimalt Harbour, Vancouver Island. {Mus. Brit.) 



This species approaches very much in sculpture to the C. corrugata 

 of Adams and Reeve (' Zoology of the Voyage of the Samarang'), 

 from the Sooloo Sea, but differs very much in shape. The peculiar 

 undulate plications are chiefly discernible near the umbones, the 

 plicae or ribs on the lower third of the shell being plain. The beaks 

 are nearly central and prominent ; the anterior extremity is some- 

 what produced, while posteriorly the shell is somewhat truncate. 

 Only one specimen was found by Mr. Lord. 



