254 PROCEEDINGS OP THE ACADEMY OF [1898. 



sembles Ariolimax. The very uarrow foot-margin, with an unusu- 

 ally distinct border above, is another distinguishing feature. 



Most of the specimens we have seen have lost the end of the tail 

 by self-amputation, as shown in the figures. When perfect the tail 

 is pointed, with no perceptible mucous pore ; the longitudinal 

 grooves of the back become irregular near the end of the tail. The 

 color of Portland and Seattle specimens is distinctly blue, but some 

 of the original lot from Olvmpia, collected about eight years ago, 

 have become brown. Mr. Cockerell thus describes a variegated 

 form which he refers to cceruleum as a variety : — 



" Prophysaon cceruleum var. dublum. Length (in alcohol) 8 mill. 

 Length of mantle, 4 mill. Distance from posterior end of mantle to 

 end of body 3£ mill. Mantle broad, with four bands composed of 

 coalesced black marbling, very irregular in shape, and running 

 together anteriorly. Body dark, tapering. Sole pale, its edges 

 gray. Liver white. With the P. cceruleum is a small dark slug, prob- 

 ably a variety of it, but differing as described above. It will easily 

 be distinguished by its blackish color and the peculiar markings on 

 the mantle." 



There are, in some specimens, very close, fine, superficial im- 

 pressed vertical lines crossing the deeper oblique grooves. 



Genus ANADENULUS Cockerell, 1890. 

 Anademdus Ckll., Ann. Mag. N. H. (6), VI, p. 279 (Oct., 1890). 



Slugs with the minute, non-spiral shell plate wholly buried ; the 

 mantle small, rounded and anterior, with breathing pore median on 

 the right side. Genital orifice below right tentacle. Foot reticu- 

 late, somewhat keeled posteriorly, the foot-margin moderate, pedal 

 grooves rising slightly at tail, with no caudal pore there ; sole dis- 

 tinctly tripartite, the areas separated by longitudinal grooves, mid- 

 dle field narrower than side fields (PI. IX, fig. 12). 



Body-cavity extending the entire length. Jaw with about 20 

 wide, flat ribs (Binney). Radula with 20-1-20 teeth, about as in 

 Prophysaon in form. 



Intestinal tract (PI. XI, fig. 35) much as in Prophysaon ; posterior 

 loop formed by G 3 and G 4 extending far behind that formed by G 1 

 and G 2 , slightly twisted posteriorly, the folds elsewhere hardly 

 twisted. 



Genital system unknown. 



Muscle system (PI. XIV, fig. 68) as in Prophysaon. Eye retract- 

 ors inserted at the two posterior angles of the diaphragm, the buc- 



