492 MANUAL OF THE M0LLT7SCA. 



external ; hmge-teeth 1 or 2 ; umbones strengthened inside by 

 a posterior lamina ; adductor («, a') and pedal impressions [p) 

 separate, slightly impressed, posterior adductor bordered by a 

 ridge ; pallial line nearly simple, sub-marginal. 



Animal with short siphons, the branchial largest, surrounded 

 at their base by 18-20 tentacles, generally reflected on the 

 shell ; mantle open in front ; foot long, narrow, and slender. 

 .(M 'Andrew.) 



Bisiribiition, 5 species. Norway, Britain, Mediterranean, 

 Madeira, Borneo, China. 40 — 150 fathoms. 



Fossil, 17 species. Neocomian — . Britain, Belgium, France, 

 South India. 



Sub-genus ? Eucharis, Eecluz ; Corbula quadrata. Hinds, 

 Guadaloupe. Bhell equivalve, obliquely keeled, gaping ; beaks 

 anterior ; hinge-teeth 1 — 1 ; ligament external ; pallial line 

 simple ; surface granulated. 



PANOPiEA, Menard de la Groye. 



Etymology, Fanope, a Nereid. 



Example, P. Americana, PI. XXII., Fig. 12. 



Synonym ? Pachymya (gigas), Sby. Upper GreDnsand. 

 Britain, France. 



Type, P. glycimeris. Fig. 267. 



Shell equivalve, thick, oblong, gaping at 'each fend ; ligament 

 external, on prominent ridges ; 1 prominent tooth in each valve; 

 pallial sinus deep. 



Animal with very long, united siphons, invested with thick, 

 wrinkled epidermis ; pedal orifice small, foot short, thick, and 

 grooved below ; gills long and narrow, extending far into the 

 branchial siphon, the outer pair much narrower than the inner, 

 faintly pectinated ; palpi long, pointed, and striated. 



In P. Norvegica the pallial line is broken up into a few 

 scattered spots, as in Saxicava; the animal itself is like a 

 gigantic Saxicava. (Hancock.) This species ranges from 

 Ochotsk to the White Sea, Norway, and North Britain ; it was 

 formerly an inhabitant of the Mediterranean, where it now 

 occurs fossil. {=^ F. Bivonce, Philippi.) The British speci- 

 mens have been caught, accidentally, by the deep-water 

 fishing-hooks. P. Natalensis is found at Port Natal, buried 

 in the sand at low water ; the projecting siphons first attracted 

 attention (doubtless by the strong jots of water they sent up 

 when molested), but the shells were only obtained by digging 

 to the depth of several feet. The Mediterranean species P. 

 glycimeris attains a length of 6 or 8 inches. 



