246 PROCEEDINGS OF THE ACADEMY OF [1898. 



genitalia). W. G. Binney, Terrestr. Moll., V, p. 238, f. 137, 138, 139, pi. v, 

 f. 1 (teeth), pi. xii, f. H (genitalia), "specimens from Mendocino County" 

 excluded. Man. Amer. Land Shells, p. 105, f. 68, 69, 70. Third Supplement 

 to T. M., V, p. 208, pi vii, f. D. Simroth, Nova Acta Acad. Cres. Leop.- 

 Carol. Germ. Nat. Cur., LVI, 1891, p. 362, pi. 7, f. 5-8 (full account of anat- 

 omy). Taylor, The Ottawa Naturalist III, p. 90. 



Prophysaon pacificum Cockerell, Nautilus III, p. Ill (Feb., 1890); V, p. 

 31 ; XI, p. 77 (includes fiavum). W. G. Binney, Third Supplement to T. M. 



V, p. 210, pi. vii, f. B. F. H. 



Prophysaon flavum Cockerell, Nautilus III, p. 111. Ann. Mag. N. H. (6), 



VI, p. 278, 279, as var. of pacificum. W. G. Binney, Third Suppl., p. 210, 

 pi. vii, f. K. 



Prophysaon Andersonii var ■. pallidum Ckll., Nautilus V, p. 31. 



Length in alcohol 25-35 mm. Upper surface buff-gray or whit- 

 ish flesh colored, with irregular blackish diamond venation and 

 sometimes suffused with purplish-black, showing a pale dorsal line; 

 the mantle yellowish, with two curved lateral black stripes, with or 

 without scattered marbling; sole pale buff or dirty white ; foot-mar- 

 gin pale ; below and anterior to mantle whitish. Integument with 

 rather coarse diamond venation, the areolae subdivided into minute 

 polygonal granules. 



Shell oval, with moderately consistent calcareous layer. 



Genitalia (PI. XIII, figs. 59, 60, 61): Epiphallus'cylindric, 

 straight or sometimes curved, with an abrupt basal constriction, 

 kink and peduncle secured by a short muscle, as described above. 

 Vas deferens very long, its length measured from end to the abrupt 

 bend at the atrium being about 7 times the length of the epiphallus ; 

 thrown into a complicated snarl. Spermatheca globose or oval, on 

 a rather slender duct. Vagina long. Free oviduct short. Ovotestis 

 showing externally a compact mass of rounded follicles. Right 

 eye retractor passing between branches of genitalia. 



Measurements of several specimens are as follows : a (Mus. no. 

 69,010, Oakland, Cal.), length of swollen epiphallus 9 mm.; length 

 of extended vas deferens, from apex of the epiphallus to base of 

 same 64 mm.; b (same locality), epiphallus 5, v. d. 36 mm.; c (Port- 

 land, Ore.) epiphallus 5.5, v. d. 37 ram. 



Jaw (PI. XVI, fig. 92, specimen from San Juan I.) arcuate with 

 about 15 well-defined ribs, denticulating the basal margin. 



Radula with 44-1-44 teeth ; rachidian tricuspid, laterals bicuspid, 

 the ectocones quite small ; marginals with moderately long, pointed 

 mesocones and minute ectocones (PI. XVI, fig. 93, two outer lateral, 

 and a group of marginal teeth). 



Alcoholic P. Andersoni varies in general tone from a smoky lead 

 color above to reddish with black marbling or suffusion, mantle light 



