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. substriata 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 Arion foliolatus of Gould has been rediscovered by Mr. 
Henry Hemphill, in Washington Territory. Specimens were sent to 
Mr. W. G. Binney, 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. Binney 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 undergoing a healing proc- 
ess.’ When the box containing the slug reached Mr. Binney, the tail-piece was 
decomposed. 
