232 PROCEEDINGS OF THE ACADEMY OF [1898. 



Intestinal tract short, crowded forward, but little twisted ; G* 

 angularly bent, forming a sort of fifth fold (PL XI, fig. 36). 



Genital system with well developed penis containing penis-papilla, 

 the retractor terminal; passing into an epiphallus. Spermatheca on 

 a short duct, inserted in atrium ; ovotestis at posterior end of vis- 

 ceral cavity, immediately under hind end of shell. 



Muscle system Ariolimacine, the eye and buccal retractors con- 

 verging posteriorly, contiguous at their proximal insertions; buccal 

 retractor spreading where it enters buccal mass, not bifurcate. A 

 broad " retensor " muscle arises at the posterior margin of diaphragm 

 just left of the retractor insertions, and runs forward as far as the 

 front insertion of the mantle (PI. XIV, fig. 69, ret.). Penis retrac- 

 tor inserted proximally on the ventral face of the retensor. Right 

 eye retractor passing between male and female branches of the 

 genitalia. 



Lung radially striate rather than reticulate. Kidney a broad 

 squarish leaf, free for the greater part, adnate dorsally around the 

 heart, (PI. XV, fig. 78). 



Distribution : Oregon, Washington and western Idaho. 



Hemphillia shares with all Ariolimacinoz the primitive arrange- 

 ment of the retractor system. Like all of this subfamily except 

 Hesperarion it possesses that anomalous muscle called by Simroth 

 the " retensor," which we hold to be a modified retractor pedis. 



Apart from these important characteristics of the musculature, 

 there are profound differences from Ariolimax and its allies : the 

 viscera are crowded forward and upward into a visceral hump under 

 the mantle, behind which the foot is solid, as in the spiral-shelled 

 snails; the shell is comparatively large and imbedded only at the 

 edges in the mantle, which exposes a considerable part of it ; and 

 the intestinal tract, while fundamentally of the same type, is con- 

 siderably shortened and simplified. 



In all of these departures from the normal slug structure, Hemp- 

 hillia is akin to Binneya; but it is a more advanced evolution-pro- 

 duct, in that it has lost the spiral torsion of the visceral mass and 

 shell, still retained by Binneya as a reminiscence of long past ances- 

 tors. 



Among the secondary characters separating Hemphillia from 

 Binneya may be mentioned the tripartite sole, narrow foot margin, 

 and small mantle lobes of Binneya, the other genus having no divis- 

 ion of the sole, no mantle lobes and a wide foot margin. Internally, 



