388 Mr. Jeffreys on the Testaceous Pneumonobranchous 



rata, tenuis, nitida, diaphana, glabra, alba. Anfractus 

 4 vix 5, convexiusculi. Apertura subrotundo-rhom- 

 boidea : peristomio vix soluto. 



Long. 0.05.— Diam. 0.175. 



Found with the last ; though much less common. It is a 

 much more depressed shell than the PL albiis, of a white 

 colour, more polished and transparent, and is destitute of 

 any markings. The upper side is uniformly more even, 

 and the under exceedingly concave. joIor> 



11. Imbricatus. 



Animal grisescens. Tentacula longa, flexilia, acuminata. 

 Testa depressa, supr^ planior, subtiis convexiuscula, um- 

 bilicata, tenuis, pellucida, transversim imbricato-stri- 

 ata, fulva, epidermide fusco lamelloso induta. An- 

 fractus vix 3 ; ultimo in carinam obtusam obliquante. 

 Apertura subrotundo-rhomboidea : peristomio soluto. 



Long. 0.015.— Diam. 0.1. 



Planorbis imbricatus. Mull. Verm. 2. p. 165. Drop. 



Hist, des Moll. p. 44. t.l.f. 49—51. 

 Turbo nautileus. Linn. Syst. Nat. 1. p. 1241, Gmel. 



Syst.Nat. 1. p. 3612. 

 Helix nautilea. Mont. Test. Brit. p. 464. t. 25. /. 5. 

 a. dupl6 minor, albida, striis rarioribus. 

 Planorbis cristatus. Drap. I. c. 



On the Iris Pseudacorus (on the decaying leaves of which 

 the animal feeds), in pools and ditches, in the autumn ; but 

 not common. 



12. NiTIDUS. 



Animal nigrum. Sustentaculwn latum. 



Testa 



