PACIFIC COAST SPECIES. 95 



Verified the identity of this form, having received it from the original 

 locality. 



In treating these various forms,* I have abstained from giving any 

 description of their exterior markings. Such description would be un- 

 reliable, as the specimens had been long jireserved in alcohol,t and are 

 evidently in various degrees of contractiou. I will say, however, that 

 I found in all the blind sac under the mouth (well marked, though not 

 very deep), which is suspected by Dr. Leidy to be the seat of the ol- 

 factory nerve. 



I can also here refer to several external characters not affected or 

 obliterated by contraction in alcohol. All the specimens have a dis- 

 tinct locomotive disk to the foot. In all, the orifice of respiration is 

 decidedly posterior to the middle of the right margin of the mantle. 

 The position of the anus I found in A. ColiimManus to be posterior and 

 inferior to the respiratory orifice, with a gutter like groove to the edge 

 of the mantle. The position of the orifice of the generative organs is 

 not so easily decided in alcoholic specimens. I have no doubt, how- 

 ever, that in the living animal it is under the mantle, not close behind 

 the right tentacle. In one form, Ariolimax Galifornicus, there are be- 

 yond doubt two distinct orifices; that of the male being smaller and 

 anterior. In Dr. Cooper's figure of ^. Califoruicus (Proc. Phila. Acad. 

 Nat. Sci., 1873, Plate III, Fig. D, 3) the two orifices are plainly shown, 

 and suggested to me the identity of my specimens with his species, es- 

 pecially as the external markings also agreed with his description. In 

 A. Columblanus also there is no common duct or cloaca, as Dr. Leidy 

 calls it, to the genitalia, though I could not detect more than one ex- 

 terior orifice. In A. niger there can be but one common orifice, judg- 

 ing from the penis entering into the common cloaca, as shown in Fig. 

 F, of Plate XII of T. M., V. The same may be said of A. Sein^MlU and 

 A. Andersoni? 



The mantle is free on its margin in its whole circumference, especially 

 in front and on its sides as far back as the respiratory orifice. I could 

 detect no concentric lines or other markings on the mantle. The mantle 

 was greatly produced and swollen on its margins in Dr. Steam's speci- 

 men of A. Californicus. In that and all the specimens examined I 

 found an internal shell, varying somewhat in thickness, but always 



* I have also examined A. Hemphilli, HecocM, and A. Andersoni. Thus I have had 

 opportunities of examining authentic specimens of all our sj^ecies. 

 t Since the above was written, I have received all the species alive. 



