126 THE NAUTILUS. 



this species is a very small, nodule-like supra-apertural lamella ; but 

 by no means constant, very often just a trace or entirely wanting. In 

 its European equivalent, V. suhstriata JefFr., this lamella is well 

 formed and constant. 



ON THE GENERIC POSITION OF ARION FOLIOLATUS, GOULD. 



BY T. D. A. COCKERELL. 



After remaining unknown and almost mythical for nearly forty 

 years, the Avion foliolatus of Gould has been rediscovered by Mr. 

 Henry Hemphill, in Washington Territory. Specimens were sent to 

 Mr. W. G. Biuney, which had been found near Gray's Harbor and 

 at Olympia, and which are referable to two different forms, as follows : 



Arion foliolatus Gould, type. One specimen agreeing with Gould's 

 description and figure, from Olympia. 



Arion foliolatus var. hemphilli W. G. Binney. Six specimens 

 from Chehalis River, near Gray's Harbor. These slugs are described 

 by Mr. Binney as " Bright yellow with bluish-black foot and edge 

 of foot ; reticulations dark reddish fawn." The genitalia also differ 

 in some details from the type, but this may be partly due to a differ- 

 ent degree of maturity. 



Mr. Biuney has kindly sent me the internal shell, genitalia, and 

 skin of the typical example, as well as drawings of both, and copious 

 notes, and at his request I offer a few remarks on the generic position 

 of the species. 



From the material I have examined, I should certainly have 

 regarded the slug as a Prophysaon with affinities to P. hemphilli. 

 But the Olympia example has lost the end of its body, ^ and the 



1 Mr. Hemphill, in his letter to Mr. Binney, relates of this example : — "When 

 I found the specimen I noticed a constriction about one-third of the distance between 

 the end of the tail and the mantle. I placed the specimen in a box with wet moss 

 and leaves, where it remained for 24 hours. When I opened the box to examine 

 the specimen I found I had two specimens instead of one. Upon examination of 

 both I found my large Prophysaon had cut off his own tail, at the place where I 

 noticed the constriction, and I was further surprised to find the severed tail piece 

 possessed as much vitality as the other part of the animal. The ends of both parts 

 at the point of separation were drawn in as if they were undergjoing a healing proc- 

 ess." When the box containing the slug reached Mr. Binney, the tail-piece was 

 decomposed. 



