the hinge margin nearly straight ; the ligament and the tooth in the flat valve very small. 



This species differs from P. rostrata in being thinner and more transparent, and in the ligament and tooth being smaller. One 

 specimen was found in Mr. G. Humphrey's collection, labelled " from Gamberoon." 



PANDORA DEPRESSA. Fig. 11 and 12. 

 P. testa ovatd, depressd, latere postico dilatato, dentibus in valvd planulutd duobus validis, in valvd altera unico maximo, 

 margine superiore subarcuato, leviter recurvo ; long. 1 T V, lat. ^\, alt. T \, poll. 

 Hab. in littoribus Insularum Maris Pacifici. 



Desc. Shell ovate, more depressed than the other species ; posterior side dilated ; valves nearly equally flat, two distinct 

 teeth in the flatter, and one very large in the deeper ; dorsal edge somewhat arched, slightly recurved. 



Very few specimens of this species, all of them much worn, were found among Mr. G. Humphrey's stock ; they have 

 apparently been worn down as if they had been used as ornaments. 



PANDORA GLACIALIS. Fig. 4 to 6. 



Leach in Capt. Ross's Voyage. 

 P. testa antice subproductd, obtuse angulatd, umbone subcentrali ; margine superiore rectiusculo, dente in valvd planulatd 

 minimo. 

 Hab. in Mari boreali. In Mus. Brit. 



Desc. Shell nearly oval, the upper margin nearly straight ; anterior side rather produced, obtusely angular ; beak nearer 

 the centre than in P. obtusa ; tooth in the flat valve very small. 



PANDORA FLEXUOSA. Fig. 13 to 15. 

 Sowerby in Genera of Shells, No. 2. 

 P. testa oblongd, gibbosiore, subrostratd; margine inferiore ftexuoso; superiore bicarinato, subarcuato, recurvo; lamina interna 

 submarginali, posticd, elongatd, in valvd planulatd: long. -^. lat. -fa, alt. -fa poll. 

 Hab. in Sinu Arabico. Mus. Goodall, nostr. &c. 



Desc. Shell oblong, rather more gibbose than in general, posterior side elongated, subrostrated ; lower edge flexuous, upper 

 bicarinated, rather arched and recurved ; a rather short tooth and an elongated, internal, subniarginal plate, on the posterior side in 

 the flatter valve. 



From the Red Sea. 



PANDORA UNGUICULUS. Fig. 16 and 17. 



P. testa oblongd, depressiusculd, postice subrostratd; margine superiore rectiusculo, extus obtuse bicarinato; antice rotundato. 

 vel subtruncato: long. /„, lat. T V, alt. -f poll. 

 Desc. Shell oblong, rather depressed, posterior side narrower, rather produced, upper margin nearly straight, with two obtuse 

 keels running from the umbo to the end of the beak: anterior side rounded or subtruncated. Never having seen the flatter valve 

 of this species, I can only state, judging from analogy, that it probably has a tooth and an elongated, subniarginal lamina within 

 on the posterior side. Locality unknown. 



PANDORA NASUTA. Fig. 18 and 19. 

 P. testa elongatd, flexuosd, postice rostrata, margine superiore postice arcuato, recurvo; antice subalato ; dente valido, ct Lvnind 

 internd submarginali, posticd, elongatd, in valvd planulatd : long. 1 fy, lat. fy, alt. T % poll. 

 Desc. Shell rather lengthened, deeper valve with a flexuous margin; posterior side of both valves beaked, their upper edge 

 arched, recurved, anterior upper edge with a small projecting wing-like appendage; a distinct tooth and an internal, elongated. 

 submarginal plate in the posterior side of the flatter valve. Two obtuse, rather obsolete ridges pass from the umbones along the 

 upper posterior edge on the outside of both valves. 



Apparently a very rare species, with whose locality I am entirely unacquainted; if the specific name rostrata had not been 

 previously occupied, I should have applied it to this as being more expressive than the one adopted. 



