DR. P. P. CARPENTER ON NEW MOLLTJSCA. 3 



nntis, posfice divergentibuSy striis incrementi crebris acutis, 

 aliter hand scuJpta ; parte antica t.jun. apertOy adultce clavsa ; 

 claims tenuissimis, secundum incrernenta undulatis, super un- 

 bones 2)rolon(/atis, umbilicos postice formantibus ; ejjidermide 

 fuc/aci, tenui, pallide viridi. 

 Hab. Monterey, Rich.; Vancouver, Lord; S. Diego, Cooper, 

 = Pholas darujinii, Sby. 

 = Jouanettia durwinii, Mus. Cuming. 

 = Parapholas penita, Tryon, Mon. Phol. 



This remarkable shell differs from Jouanettia in having both 

 valves equal ; from Pholadidea proper in having no coriaceous 

 cup, its place being supplied by a flattened prolongation from 

 each valve, like a duck's bill in miniature. In Mr. Lord's specimen 

 (preserved in the British Museum), though the valves are closed, the 

 prolongations are widely divergent, as when the bird utters its cheer- 

 ful " quack." The loose, thin epidermis appears to have covered the 

 bill as well as the valves. Mr. Tryon had probably not seen a speci- 

 men, else he could hardly have affiliated so very different a shell to 

 Pholadidea penita. The original specimen is said to have come from 

 ChiU. 



Darina declivis. 



D. t. tenuissima, planata, eUiptica, Machceraformi, utroque latere 

 hiante ; cinerea, epidermide fortiore induta ; marginihus regu- 

 lariter excurvutis ; umbonibus haud conspicuis, ad duas inter 

 quinque partes longitndinis postice sitis : intus cartilagine 

 spathula elongata, dorsum versus utraque valva decliviter sita, 

 a ligamento lamina extante tenuissima separata ; dente car- 

 dinali laminato, extante, curtiore ; lateralibus vix conspicuis ; 

 sinu pallii ovali, fere ad medium porrecto. 

 Long, \-77i lat. -85, alt. -34 poll. 

 Hab. Vancouver's Island (Forbes). 



The only other species of Darina known is from the Straits of 

 Maghellan. The northern shell may have been passed over as the 

 young of Machcera patula, to which it bears a strong external re- 

 semblance. 



Saxidomus brevisiphonatus. 



S. t. subovaliy tenuiore, subplanata, albida, epidermide pallide 

 olivacea induta ; tota svperjicie rugis concentricis, crebris, 

 valde obtusis, et undis incrementi interdum majoribus, ornata ; 

 marginibus subcequaliter excurvatis, maxime ventrali : intus 

 cardine tenuiore, dente antico elongato ; sinu pallii parvo, ad 

 trientem interstitii porrecto, latiore. 

 Long. 2-65, lat. 2-05, alt. ri.5 poll. 

 Hab. ?Vancouver, ? Japan {Mus. Cuming), 



A very distinct species, in shape and hinge not unlike Callista, but 

 without lunule. It is more rounded and flatter than the three ty- 

 pical Californian species, and known at once by the very small mantle- 

 bend. From four to six blunt riblets are seen on each of the very 



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