74 



umbonem tegente sed non adnato, callum dentiformem instructo : 

 cochlea subulata, arcuata : cavositatead undas, costas et tubercu- 

 los indentato. Long. 3; lat. If; alt. If poll. Hab. Philippine 

 Islands. 



The shell most nearly approaching to this is P. latissi?na, 

 Sowb., and possibly may be the same species. It also resembles 

 P. truncata. It is remarkable for the breadth of the valves. 



Solen scalprum. Testa transversa, oblonga, retrorsum dila- 

 tata, fere unilateralis, tenuis, lucida, epidermide flavo-viridi, 

 nitido, iridescente induta ; latere antico sub-acuto, oblique rotun- 

 dato ; latere postico semicirculari : cardo dentibus duobus con- 

 tiguis, divergentibus in v. dextra ; dente subulato, arcuato in v. 

 sinistra ; margine cardinali costa alba submarginali suffulto : 

 interior albida. Long. If; lat. f ; alt. T 3 5 poll. Hab. Singa- 

 pore. 



Allied to Solecurtus costatus and radiatus. The hinge margin 

 is fortified by a thickening, and indeed there is the vestige of a 

 rib passing from the beak to the ventral margin. 



Solen sicarius. T. transversa, oblonga, retrorsum angustata, 

 sub-falcata, epidermide crasso, nitido, corneo induta, antice ob- 

 lique truncata, postice rotundata : valvis valde excavatis, undu- 

 latis, in areis triangularibus indistincte partitis ; margine dorsali 

 recto; m. ventrali arcuato ; natibus terminalibus : cardo dente 

 triangulari, erecto, recurvo in utraque valva instructus. Long. 3£ ; 

 lat. 2- 7 , T ; alt. T 9 ff poll. Hab. Straits of De Fuca, Oregon. 



The only species to which this bears any resemblance is <S. 

 viridis, which has nearly the same hinge and general form, but 

 which is a more delicate and more slender shell. 



Panopjea Antarctica. T. subquadrata, crassa, alba, rudis, 

 concentrice undata, postice truncata, antice angusiata et rotun- 

 data ; margine cardinali erecto, margine ventrali arcuato; urn- 

 bonibus latis, elevatis, fere medianis : cardo dente parvo, conico 

 instructa : sinu palleali lato, arcuato, minime impresso; cicatrice 

 musculari postica discreta, crescentiformi. Long. 2£ ; alt. 2 ; 

 lat. l£. Hab. Rio Negro, Patagonia. 



Besides being destitute of ribs, it is more nearly equilateral 

 than P. arctica, and has the beaks more posterior. It is less 

 gaping, and the posterior truncation is scarcely oblique. 



