243 MANUAL OF THE MOLLUSCA. j! 



■'t 



L. Norvegica ranges from Norway to the sea of Ochotsk ; in 15 — 80 fms. ; 



Fossil ? Miocene — . Europe. (100 sp. L. Sil. — . D'Orb.) ! 



? Entodesma (Chilensis) Phil. Shell thin, saxicava-shaped, slightly in- \ 



equivalve and gaping, covered with thick epidermis ; hinge edentulous ; each ] 



valve with a semi-circular process containing the cartilage. . ; 



Pandora (Solander) Brug. \ 



Type, P. rostrata, PI. XXIII. fig. 11. {Pandora, the Grecian Eve.) ' 



Shell inequivalve, thin, pearly inside ; valves close, attenuated behind ; 

 right valve flat, with a diverging ridge and cai'tilage furrows; left valve 

 convex, with two diverging grooves at the hinge ; paUial line slightly sinuated. \ 

 Outer layer of regular, vertical, prismatic ceUs,"250 times smaller than those ' 

 of Pm;j« (fig. 260). {Carpenter.) 



Animal ^vith mantle closed, except a small opening for the narrow, 

 tongue-shaped foot ; siphons very short, united nearly throughout, ends ] 

 diverging, fringed; palpi triangular, narrow; gills plaited, one on each side, j 

 with a narrow dorsal border. | 



Distr. 13 sp. C. States, Spitzbergen, Jersey, Canaries, India, N. i 

 Zealand, Panama: 4 — 110 fms. burrowing in sand and mud. j 



Fossil, 4 sp. Eocene — . U. States, Brit. 



Myadora, Gray. | 



Ttfpe, M. brevis, PI. XXIII, fig. 12. ; 



Shell trigonal, rounded in front, attenuated and truncated behind ; right j 

 valve convex, left flat; interior pearly; cartilage narrow, triangular, between .] 

 2 tooth-like ridges in the left valve, with a free sickle-shaped ossicle; pallial \ 

 line sinuated : structure like Anatina ; outer cells large, rather prismatic. 



Di^tr. 10 sp. N. Zealand, N. S. Wales, Philippines. 



Myochama, Stutchbury. 



Type, M. anomioides, PI. XXIII. fig. 13. 



Shell inequivalve, attached by the dextral valve and modified by form of 

 surface of attachment ; posterior side attenuated ; left valve gibbose ; carti- , 

 lage internal, between 2 tooth-like projections in each valve, and furnished 

 Avith a moveable ossicle ; anterior muscular impression curved, posterior 

 rounded, pallial sinus small. 



Animal with mantle-lobes united ; pedal opening and siphons surrounded i! 

 by separate areas ; siphons distinct, unequal, small, slightly fringed ; a minute \ 

 fourth orifice close to the base of the branchial siphon ; visceral mass large, 

 foot small and conical ; mouth rather large, upper lip hood-Hke ; palpi 

 tapering, few-plaited ; gills one on each side, triangular, plaited, divided by 

 an oblique line into two portions ; excurrent channels 4, 2 at the base of the 

 gills and two below the dorsal laminae. (Hancock, An. Nat. Hist. 1853.) 



