250 PROCEEDINGS OF THE ACADEMY OF [1898. 



larly mottled with fuscous, and has one broad fuscous band down 

 the center of the back, spreading as it joins the mantle, with a nar- 

 rower band on each side of the body. It loses its color on being 

 placed in spirits, becoming a uniform dull slate color. Mantle 

 lengthened oval. Shell-plate represented by a group of calcareous 

 grains concealed in the mantle ; it is impossible to remove it as one 

 shell-plate. A decided caudal pore." The jaw and dentition are 

 as in folio latum. Genitalia much as in foliolatum, but Binney found 

 the albumen gland to be much shorter, less tongue-shaped and 

 brown-tipped. The epiphallus tapers distally, instead of contract- 

 ing abruptly. 



Localities : Gray's Harbor and Chehalis, Washington. 



The only characters of importance are the dorsal band, which 

 seems to be similar to P. fasciatum, and the tapering epiphallus, also 

 a character of that species, if not, in this case, an indication of sex- 

 ual immaturity. Mr. Cockerell considers it a synonym of foliolatum ; 

 and, as we have seen no authentic specimen, and the name is, in any 

 case, preoccupied, we consider it best to leave the form as a syno- 

 nym of foliolatum, pending further information. 



In a series from Cascade Springs, on the Columbia River near 

 the Government locks, collected in October, 1897 by Mr. J. G. 

 Maloue, (PI. XIII, fig. 54) the epiphallus is shorter, not curved, the 

 vas deferens also much shorter. The spermatheca is subglobular. 

 Measurements : length of epiphallus 8.6 mm. ; of extended vas 

 deferens from apex of the epiphallus to the abrupt curve at base of 

 same, 42 mm. ; of albumen gland 13 mm. ; length of animal 50 mm. 

 As measured above, the epiphallus is about one-fifth the length of 

 the vas deferens. In typical foliolatum it is about one-eighth, in 

 Andersoni one-seventh. These specimens are (in alcohol) less ver- 

 miform than typical foliolatum, with paler color, back including 

 shield, reddish, fading on the sides ; mantle striped as usual, but 

 blackish stripes defining the dorsal pale stripe either very faint or 

 lacking, so that in some individuals no pale dorsal line is visible. 



Thejaw in this form (PI. XVI, fig. 89) resembles that of P. Ander- 

 soni in the numerous ribs. Radula with long, pointed mesocones on 

 outer lateral and inner marginal teeth, as in P. Andersoni. In 

 typical P. foliolatus the corresponding teeth are shorter and blunter. 



This will probably prove to be a distinct subspecies, and re- 

 ferable to P. Andersoni rather than to foliolatum. 



