160 



chial siphons than the Mediterranean P. Aldrovandi, while the siphons are 

 more separated at their extremities, and the impressed mark of the mantle 

 on the shell presents a broken appearance at the edge. 



1. abbreviata, Vol. 



2. Aldrovandi, Lam. 



3. antarctica, Gould. 



4. australis, Soto. 



Species. 



5. generosa, Gould. 

 G. Japonica, Adams. 



7. Middendorfii, id. 



8. Natalensis, TFoodw. 



9. Norvegica, Speuy. 



10. Solandri, Gray. 



11. Zelaudica, Quoy. 



Figure. 



Panop^ea Aldrovandi. PI. 0. Shell, with the animal, its siphonal 

 sheath being much contracted from being preserved in spirits. Prom a 

 specimen in the Gloucester Museum, brought alive to the Rev. L. B. 

 Larking while residing at Messina. 



Genus 12. GLYCIMERIS, Lamarck. 



Animal; with the mantle thickened, and closed except in front, for 

 the passage of a small foot ; siphons united in a very fleshy 

 cylindrical mass, never withdrawn within the shell. fAudouin.J 



Shell ; equivalve, gaping widely at doth ends, of thick opake-white 

 substance, covered with a hard, black, horny epidermis ; hinge 

 toothless, composed of a thickened fulcrum supporting a rather 

 lengthened external ligament. 



Allied to Panopcea, and of similar habits, is another genus, Glycimeris, 

 of which the shell has in like manner an external ligament supported on a 

 thickened fulcrum, while the siphons of the animal are also extended and 

 united within a leathery wrinkled sheath. Internally the shell is a peculiar 

 opake-white substance, showing in unusually strong relief the impression 

 of the soft parts ; externally it is covered with a hard, shining-black, horny 

 epidermis, passing somewhat over the margin. The Glycimeris, of which 

 there is only a single species, is strictly a native of the Arctic Seas. 





