350 



It is frequently covered with a concreted, ftony matter, 

 and fometimes a brown epidermis : dead fhells are white. 



Although by no means a fcarce fpecies, it has been in 

 confiderable obfcurity, notwithftanding Petiver gave 

 a figure of it near a hundred years ago, and fays, "I 

 have obferved this in frefli-water, and if I miftake not, 

 in the New River" 



MuLLER has doubtlefs given this fhell in two places, 

 but in neither does he mention the fmgular ftrufture of 

 the animal inhabitant ; a circumflance that would not 

 have efcaped the difcriminating eye of that great natu- 

 ralift, if it had ever come alive under his examination. 



ScHROETER has glvcu it in no lefs than three places, 

 as fo many diftinft fpecies ; two of which are evidently 

 thofe of MuLLER : the other under the title of Trochus 

 crijfatus, defcribes both the fliell and the animal per- 

 fetlly well: he fays he received it from Profelfor Her- 

 mann, by the name of Federbufchtragers (plume-bear- 

 er), by which appellation it is alfo to be found in Mar- 

 tini Berlin Maffiz. iv. 247. No. 59. Geoff ROY in his 

 German edit, calls it Cochlea deprejfa crijlata: in his 

 French edit. Le Port Flimict. 



From thefe authors it appears to have been found in 

 water courfes, fmall flreams, and fiOi-ponds, dihonx. Paris, 

 as well as in Szoeden, 



The 



