248 PROCEEDINGS OF THE ACADEMY OF [1898. 



from Gray's Harbor, Washington, is to be included in P. pacificum. 

 There are all possible intergradations between the ochreous and 

 grayish forms in P. Andersoni and P. folio latum. 



In P. pacificum we fail to see any specific characters. The color- 

 ation agrees well with specimens of undoubted P. Andersoni from 

 Washington, and neither the measurements nor the dentition offer 

 differential characters, so far as we can see. The types were col- 

 lected by Mr. Wickham, near Victoria, Vancouver Island. 



P. foliolatum (Gould). PI. X, figs. 15, 16, 1 7 ; PI. XI, fig. 32 ; PI. XIII, figs. 55, 56, 

 57, 58; PI. XIV, fig. 70 ; PI. XV, fig. SO ; PI. XVI, figs. 90/ 9S. 



Arion foliolatus Gould, Moll. U. S. Expl. Exped., p. 2, PI. I, f. 2a, b (1852); 

 Binney. Terr. Moll , II, p. 30. PL 66, f. 2 (1851 ). Copied by subsequent writ- 

 ers. W. G. Binney, Second Supplement to Terr. Moll., V, p. 206, PL viii, 

 f. A, B, PL ix, f. B. C, D. 



Phenacarion foliolatus CklL, Nautilus., iii, p. 127 (March, 1890); Ann. 

 Mag. N. H. (6). VI, pp. 278, 279; W. G. Binney, Fourth Supplement, p. 181. 



Arion foliatus W. G. Binney, Proc Acad. Nat. Sci. Phila., 1858, p. 197. 



Arion foliolatus var. Hemphilli W. G. Binney, Third Supplement, T. M. V, 

 p. 208, PL viii, f. C; ix, f. H (genitalia). Cockerell, Nautilus III, p. 126 

 (March, 1890). 



Phenacarion Hemphilli W- G. Binney, Fourth Supplement toT. M. V, p. 183 

 (not Prophysaon Hemphilli Bid. & Binn.). 



Length (in alcohol) 50-80 mm. Rather slender, the posterior 

 third (or more) often distinctly more attenuated, defined by an ob- 

 lique groove. Mantle oblong, its length contained 2f to o\ times in 

 the total length of body, the breathing orifice decidedly in front of 

 the middle. Foot margin rather wide; wrinkles of the sole corres- 

 ponding to vertical grooves of the foot margin, bending backward 

 and meeting in the middle ; pedal groove deep, with no noticeable 

 caudal pore. 



Colors variable : (1) Back clear reddish-fawn with a lighter dor- 

 sal band, sometimes obsolete, the mantle with the usual two curved 

 black lateral stripes, with or without scattered macula? ; becoming 

 paler, light yellowish on the sides and sole; or (2) back reddish, 

 suffused with black, mantle bands long, often with a third median 

 band and scattered maculae, foot with the principal veins of the 

 reticulation black-pigmented, as are alternate grooves of the foot 

 margin ; sides paler, gray ; sole yellowish. 



Surface with deeper oblique grooves connected by short longi- 

 tudinal grooves to form a roughly diamond-shaped reticulation, the 

 meshes of which are minutely subdivided. 



Shell very delicate, membranous, with a thin and incoherent 

 layer of calcareous granules. 



