384 Mr. Jerrreys on the Testaceous Pneumonobranchous 
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 different from any other British 
 Planorbis; and has somewhat the form of the last. ‘The 
whitish bands remarked by Shróter on the body volution j 
of his specimens are wanting in this. 
5. UMBILICATUS. 
Animal nigrescens. Tentacula rufa. (Müll.) 
Testa supra umbilicata, subtis plana, subperforata, carina 
marginali distincta, tenuis, substriata, flavescenti-cor- 
nea. Anfractus 5—6, rotundati, globosi. Apertura 
subrotundo-rhomboidea. 
Long, 0.175.—Diam. 0.6. 
Planorbis umbilicatus. Müll. Verm. 2. p. 160. 
marginatus. Drap. Hist. des Moll. p. 45. 
t. 9. f. 11, 12. 
Helix complanata. Linn. Syst. Nat. 1. p. 1249. Dillo. 
Cat. 2. p. 897. 
—-— Planorbis. Penn. Brit. Zool. 4. p.133. t. 83. 
f. 123. Maton & Rackett in Linn. Trans. 8. p. 188. 
1.5. FB 
^m ditches, &c. Young shells show ‘scarcely any trace of 
a keel; and, independently of the oreater 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. p imp im. o x 
Animal fuscum. Tentacula incurvata, opaca. — — 
= | Testa 
