464 Miscellaneous. 



On the Teeth of the Black and Wood Shell SluffS. 

 By Dr. J. E. Gray, F.R.S. &c. 



Razoumowsky, in his Natural History of Jorat, and Sturm, in 

 the German Fauna, separated the Black Shell-slug as a distinct spe- 

 cies, the first under the name of Limax ater, and Sturm under that 

 of Limax cinereo-niger. Ferussac regarded it only as a black variety 

 of Limax cinereus, and most authors, except Nilsson, have followed 

 his example. Herr Otto Goldfuss, in a paper on the Land and 

 Freshwater Mollusca of the Rhine Province and Westphalia, has 

 proved, by the examination of the teeth, that the German Black 

 Slug is quite distinct from the usual streaked Limax cinereus : the 

 teeth in the latter are thick, conical, acute, and quite simple ; while 

 in the black species they are slender, subcylindrical, attenuated to 

 a fine point, and have a strong denticulation or notch on the front 

 side, at some distance below the tip. 



I may further observe, that the teeth of Limax sylvaticus, which 

 has been considered as a doubtful species, and which Ferussac thought 

 was a variety of L. agre'stis, are, according to the same author, ex- 

 ceedingly unlike the teeth of any other European Slug. The upper 

 process of the tooth in this species is short, cylindrical, truncated, 

 and rounded at the tip ; while in all the others it is tapering and acute. 



It is desirable that the teeth of English s])ecimens should be 

 examined, to find if the same difference exists in those species natives 

 of this country. 



This is an example of what I have long believed, — that the teeth 

 afford very good characters for the separation of allied species, as 

 well as for the distinction of genera and families. Such examples 

 have long made me feel that we should be very cautious in consider- 

 ing specimens which are similar in the form of the shell and general 

 appearance of the animal, as the same species, when they come from 

 different localities and are said to have different habits, unless we 

 have examined the teeth and other characteristic parts ; and such 

 facts as the above must always render the identification of fossil shells 

 with recent species very problematical. 



Note on the Anatomy q/Cyclostoma elegans. By E. Claparede. 



The most remarkable peculiarity presented in the anatomy of 

 Cyclostoma elegans is the presence of an organ, of a brilliant white 

 colour, lodged among the convolutions of the intestine. This organ, 

 which has no analogue in any other known moUusk, contains a mul- 

 titude of solid concretions, of concentric structure, composed of an 

 organic skeleton and incrusting salts. The salts consist in part of 

 carbonate of lime, partly of a salt not chemically determined, soluble 

 in hydrochloric acid. This salt is not an oxalate ; for it is also 

 soluble, after a time, in acetic acid. An analogous gland exists in 

 the Cyclostoma costulatum of the Banat. The author ascertained 

 that the stiff silky hairs which are found on the skin of the fresh- 

 water Neritina exist in most of our freshwater Mollusca {Lymntea, 

 Planorbis, Bithynia). — Miillers Archiv, 1858, i. p. 1. 



