386 Mr. Jzerrreys on the Testaceous Pneumonobranchous 
rinatus in his Einleitung to the Helix complanata of Linnzus, 
he has not separated the other two. His fig. 13. Pl. V. of the 
Flussconchylien is an exact representation of the PL. lutes- 
cens ; and in speaking of his ** Heliz planorbis crassa" (our 
Pi. umbilicatus), he says, “ The specimen from Hamburgh is 
black, with the keel sharp and visible on both sides. 
Much confusion existed in Müller's time as to the Helix 
Planorbis and complanata of Linnzus; nor has it been in 
any wise removed by succeeding authors. In their eager- 
ness to adapt their new discoveries to the pages of that 
illustrious naturalist, they seem to have lost sight of the 
circumstances under which even the latest edition of the 
Systema Nature was written, and to have given him credit 
for trivial distinctions, which it was scarcely possible could, 
in that state of science, have been attended to, and which 
often they themselves but imperfectly understood. The 
Helix Planorbis of that work has been referred by the three 
authors who have last treated on the subject of British Con- 
chology, to as many distinct species; and nearly as great 
uncertainty has prevailed as to the true H. complanata. 
8. DRAPARNALDI. 
Animal — 
Testa utrinque sübumbiliaids perforata, cariná media sub- 
prominulà, lateribus zequalibus, tenuis, pellucida, gla- 
bra (sub lente transversim argutissimé striata), lutes- 
centi-fusca. Anfractus 5, convexiores. Apertura dila- 
tata, subrotundo-rhomboidea : peristomio libero. 
Long. 0.1.— Diam. 0.325. 
3 | Planorbis ie er. Hist. des Moll. p. 45. t. 2. 
Piinorbis 
