1898.] NATURAL SCIENCES OF PHILADELPHIA. 251 



P. humile Cockerell. PI. XVI, fig. 97. 



Prophysaon humile Cockerell, Nautilus, iii, p. 112 (February 1890), Ann. 

 Mag. N. H. (6), VI, p. 277, 279. W. G. Binney, Third Suppl., p. 211, PI. 

 ViL figs. E, G, L, M. 



We do not consider P. humile 19 specifically distinct from fasciatum. 



The coloration, genitalia and teeth are practically identical, and the 



character of the jaw (PI. XVI, fig. 97) does not seem to be constant. 



Several specimens selected at random from our series of fasciatum 



from Seattle have a jaw neither plaited or ribbed, but densely, 



irregularly striated. We cannot find any other differences between 



these specimens and the ordinary fasciatum with flat-ribbed or 



plaited jaw. The name humile has precedence over fasciatum and 



if the two forms prove to be, as we think, specifically identical, 



fasciatum will be reduced to varietal rank. 



P. fasciatum Cockerell. PI. X, figs. 23-27 ; PL XI, fig. 34; PI. XII, figs. 37-40; 

 PL XVI, figs. 91, 94-96. 



Prophysaon fasciatum Cockerell in Binney, Third Supplement to Terr. Moll., 

 V, p. 209, pi. vii.f. A (May, 1890). W. G. Binney, Fourth Supplement, p. 

 180, Cockerell, Ann. Mag. N. H. (6), VI, p. 278, 279. 



Prophysaon Hemphilli, ''specimen from Mendocino County," W. G. Binney, 

 Terr. Moll., V, p. 239, pi. xii, f. I. 



Prophysaon Andersoni J. G. C. , W. G. Binney, Second Supplement, p. 42. 



Prophysaon fasciatum var. obscurum Ckll. The Conchologist II, p. 119 

 (Chehalis, Wash.) 



Length (in alcohol) 25-35 mm., rarely as much as 50 mm. Gen- 

 eral form and surface reticulation as in P. Andersoni. Color ex- 

 tremely variable : (1) Whitish-buff, (2) bluish-gray, or (3) red on 

 the back, gray-buff at the sides, always with two conspicuous black 

 stripes (well- or ill-developed) along the sides behind the mautle, 

 defining a wide, wedge-shaped ligbt dorsal area, which encloses a 



19 The original description is as follows : " Prophysaon humile Cockerell — 

 Length (in alcohol) lrj.V mill. Body above and mantle smoke-color, obscured 

 by bands. Mantle wrinkled, and having a broad dorsal and two lateral black- 

 ish bands, reducing the ground-color to two obscure pale subdorsal bands. 

 Length of mantle 7 mill., breadth 5i mill. Respiratory orifice 2| mill, from 

 anterior border. Body subcylindrical, somewhat tapering, rather blunt at 

 end. Distance from posterior end of mantle to end of body 8 mill. Back 

 with a blackish band reaching a little more than half its length, and lateral 

 darker blackish bands reaching its whole length. Reticulations distinct, 

 " foliated." Sole strongly transversely striate-grooved, but not differentiated 

 into tracts. Jaw pale, strongly striate, moderately curved, not ribbed. Lin- 

 gual membrane long and narrow. Teeth about 35-1-35. Centrals tricuspid, 

 laterals bicuspid, marginals with a large point, and one (sometimes two) small 

 outer points. Liver pale chocolate. 



Found by Mr. A. F. Wickham under the bark of rotten logs in the woods 

 around Lake Co?ur d'Alene, Idaho, 1889. 



In its reticulations and general characters this species resembles P. Ander- 

 soni, of which it is possibly a variety." 



