Species of the ^rf^n^^v Geomalacus. 273 



is no wonder that, when once an erroneous generic designation 

 liad been given to a young Arioiiy the number of species could 

 be most readily increased. 



The substitution has doubtless been no easy task for Mabille 

 in the composition of his monograph ; but he must have formed 

 for himself a totally different conception of the animal, which 

 had hitherto been described by English authors only, though 

 with sufficient distinctness. In his generic diagnosis Mabille 

 states that the animal is ornamented with an infinite number 

 (" d'une infinite") of minute black, yellow, golden, white or 

 silvery dots, which, by the by, is by no means correct ; anct 

 in his improved specific diagnosis he even amends the original 

 English descriptions in so cool a manner that I am astonished 

 that English malacologists should not have replied to it. 

 Mabille says, in the same diagnosis, that the English drafts- 

 men, instead of covering the body of this slug with a multi- 

 tude of rchite dots, had contracted the same upon the wrinkles, 

 and, to facilitate the labour, had united them into 07ie single spot 

 on the different wrinkles. And this he states to be the reason 

 why the Geomalacus appeared to be a black animal with lon- 

 gitudinal lohite ridges or hillocks^ which he says is qnite 

 incorrect ! 



This statement of itself suffices to convince us that Mabille 

 has never seen a living Geomalacus ; for what he supposes to 

 be altogether incorrect is precisely the actual fact. The Geo- 

 malacus is not covered with white or yellow dots, but with 

 actual longitudinal spots extending on the back of the animal 

 over one or two of the wrinkles. These spots are even dis- 

 tributed on a black ground in such a manner that they might 

 easily be counted ; and the drawings of Allman (Andrews) are 

 quite correct. 



Mabille's description of the respiratory orifice as being con- 

 siderably in front ("tr^s-anterieur") corresponds admirably 

 with that of a young Arion. The original diagnosis says, "a 

 Limace (differt) situ anterior! spiraculi;" for in Limax the 

 respiratory orifice is situated behind the middle of the mantle, 

 and not in front of it. 



Further, incorrect is ]\Iabille's statement respecting the 

 internal shell — namely, "Limacelle dtilicate, excessivement 

 plate;" and,fm-ther,"SaLimacellemincecommennepellicule." 

 The original diagnosis says " Testa solida;" and, indeed, its 

 thickness attains almost a third of its length, and nearly the 

 half of its breadth. The shell is consequently by no means 

 "delicate," and much less "mince" or "plate," but actually 

 very solid — in fact, as solid as we rarely meet with internal 

 hells, to whatever genus they may belong. 



Ann. & Mag. N. Hist. Ser. 4. Vol.xi. 18 



