CONCHIFEKA. 307 



or Finely fringed ; freely open in front ; siphons moderate, separate half-way 

 or throughout, orifices fringed, anal cirri simple, branchial ramose ; palpi 

 long, triangular. 



Distr. 78 sp. Norway, Brit. Black Sea, Senegal, Brazil, India, China, 

 New Zealand. Low- water 100 fms. (Beechey). 



Fossil, Miocene . Brit. France, Belgium, Italy. 



The animal is eaten on the continental coasts ; it buries in the sand at 

 low-water or hides in the crevices of rocks, and roots of sea-weed. 



VENERUPIS, Lamarck. 



Etym. Venus^ and rupes, a rock. Syn. Gastrana, Schum. 



Example, V. exotica, PL XX. fig, 15. 



Shell oblong, a little gaping posteriorly, radiately striated and ornamented 

 with concentric lamellae ; three small teeth in each valve, one of them bifid ; 

 pallia! sinus moderately deep, angular. 



Animal with the mantle closed in front, pedal opening moderate ; siphons 

 united half-way, anal with a simple fringe and tubular valve, branchial 

 siphon doubly fringed, inner cirri branching ; palpi small and pointed. 



Distr. 19 sp. Brit. Crimea ; Canaries ; India, Tasmania ; Kamts- 

 chatka, Behring's Sea Peru. In crevices of rocks. 



Fossil, Miocene . U. States, Europe. 



PETRICOLA, Lamarck. 



Etym. Petra, stone, colo, to inhabit. 



Syn. Rupellaria, Bellevue ; Choristodon, Jonas ; Naranio, Gray. 



Type, P. lithophaga, PI, XX. fig. 16. f>. pholadiformis, PI. XX. fig. 17. 



Shell oval or elongated, thin, tumid, anterior side short ; hinge with 3 

 teeth in each valve, the external often obsolete ; pallial sinus deep. 



Animal with the mantle closed in front, much thickened and recurved 

 over the edges of the shell ; pedal opening small ; foot small, pointed, lanceo- 

 late ; siphons partially separate, orifices fringed, anal with a valve and simple 

 cirri, branchial cirri pinnate ; palpi small, triangular. 



Distr. 30 sp. U. S. France, Red Sea, India, New Zealand, Pacific, W. 

 America (Sitka Peru). Burrows in limestone and mud. 



Fossil, 12 sp. Eocene . U. S. Europe. 



GLAUCOMYA, (Bronn) Gray. 



Syn. Glauconome, Gray 1829 (not Goldfuss 1826). 



Type, G. Sinensis, PI. XX. fig. 18. (Glaucos sea -green, my a mussel.) 



Shell oblong, thin ; epidermis dark, greenish ; ligament external ; hinge 

 with 3 teeth in each valve, one of them bifid j pallial sinus very deep and 

 angular. 



Anwud with a rather small, linguiform foot ; pedal opening moderate ; 



