384 Mr. Jeffreys on the Testaceous Pneumonobranchous 



H'- A single dead specimen only has as yet occurred to me 

 of this curious shell, which was found in Crymlyn Bog near 

 Swansea. It is totally diiFerent from any other British 

 Planorbis; and has somewhat the form of the last. The 

 whitish bands remarked by Shroter on the body volution 

 of his specimens are wanting in this. 



5. Umbilicatus. ^_^,,„,.r_5...^. 



JmmaZnigrescens. Tent acula ruf a. {Miill.) 

 Testa supr^ umbilicata, subtils plana, subperforata, carind 

 ,r ;,;o: margiuali distiucta, tenuis, substriata, flavescenti-cor- 

 ; ^v nea. Anfractus 5 — 6, rotundati, globosi. Apertura 



subrotundo-rhomboidea,, ,^ , ,; , .n^oi..»^vi 

 Long. 0.175.— Diam. 0.6. • 



Planorbis umbilicatus. Mull. Verm. 2. p. 160. 

 marginatus. Drop. Hist, des Moll. p. 45. 



t.2.f. 11, 12. 

 Helix complanata. Linn. Syst. Nat. 1. p. 1242. Dillw. 



Cat. 2. p. 897. 

 Planorbis. Penn. Brit. Zool. 4. p. 133. t. 83. 



/. 123. Maton ^ Rackett in Linn. Trans. 8. p. 188. 



^.5./. 13. 



In ditches, &c. Young shells show scarcely any trace of 

 a keel ; and, independently of the greater thickness and 

 convexity of the volutions, they cannot be mistaken for the 

 following, in which the carina is in every stage of growth 

 equally distinct on both sides, owing to the greater slope of 

 the body whorl. 



6. Carinatus. 



Animal fuscum. Tentacula incurvata, opaca. 



Testa 



