"240 PROCEEDINGS OF THE ACADEMY OF [1898. 



P. B. Randolph. A specimen much contracted in alcohol is here 

 figured, with the retractor system and pallial organs. As preserved 

 they measure 15 to 20 mm. in length ; ground-color above dirty 

 ■whitish, with a conspicuous blackish stripe along each side of mantle 

 and of the foot behind it, the back with a broad median bluish or 

 slate-black band, tapering posteriorly, often only faintly indicated ; 

 sole light yellow. 



In other specimens from Poughkeepsie, N. Y., the region between 

 the longitudinal black bauds on mantle and sides is speckled and 

 maculated with black. 



As this species is an immigrant from Europe, where it is well 

 known and has been repeatedly investigated anatomically, we omit 

 a detailed description and synonymy. The coarsely, longitudinally 

 rugose integument, anterior position of the breathing orifice, and 

 posterior position of the genital orifice, below the other, readily dis- 

 tinguish Avion from all native American slugs. 



Arion sp. 



W. G. Binney describes a slug referred by him to Avion fuscus 

 Miiller, from Boston, Mass. Mr. Cockerell considers it likely that 

 the figure in Terrestrial Mollusks, PI. LX1V, fig. 1, (copied in Man. 

 Amer. L. Shells, fig. 502) represents A. subfuscus. Whether more 

 than one species of Avion occurs in America will remain doubtful 

 until further examination of the Bostonian slug can be made. 



Genus PROPHYSAON Bland & Binney, 1873. 



Prophysaon Bland & Binney, Ann. Lye. Nat. Hist. N. Y., X, 1873, p. 293; 

 type P. hemphilli B. & B. Cockerell, Ann Mag. N. H. (6), VI, p. H77-279, 

 and Nautilus XI, p. 77 (key to species). — W. J. Raymond, Nautilus. IV, p 6 

 (mutilation of tail). 



Phenacarion Cockerell, Nautilus III, p. 127 (March, 1890), type Arion 

 foliolatus Gld. The Conchologist II, p. 118. 



Slugs with anterior shield-like mantle in which the flat, non-spiral 

 shell is completely buried, the breathing pore in front of the middle 

 of its right margin ; genital orifice behind and near right tentacle. 

 Foot reticulated, the areolae subdivided (except in ccevuleum) ; the 

 coloration in two or three longitudinal bands on mantle or mantle 

 and foot, or monochromatic. Foot-margin wide, pedal furrows deep, 

 with no noticeable caudal pore (or only a small slit, in P. foliolatum, 

 hardly or not visible in alcoholic specimens). Sole not in the least 

 tripartite. Tail usually showing an oblique constriction at from the 

 posterior third to sixth of the animal's length, marking the place 

 where self-amputation takes place. 



