THE NAUTILUS. Uh 
“Ariolimax columbianus, from W.G. Binney, 45 mm. long. 
“ Really, there is no external difference between these slugs !—at 
least, nothing specific. Californicus is more keeled, and has a nar- 
rower sole (sole lat. of ca/. 11, of columb.13 mm.). Sole of columb. 
is unicolor grayish ochre, that of calif. has lateral tracts grayer ; both 
are transversely wrinkled. Reticulations on body appear to me to 
be the same. In color both are ochreous, co/wmb. has black mot- 
tling on body (v. maculatus Ckll.) ; calif. has similar black marbling 
on body, but mantle, instead of being unicolor, hasa large black 
spot, diam. 6 mm., over place of shell (v. maculatus, noy.). This 
spot on mantle is in fig. of colwmb. mac. in Binney, PI. vi, f. A.” 
(Ckll. MSS.). 
Ariolimax costaricensis. 
Here again our authors must be convicted of hasty judgment. 
They complain that there is nothing in the description to identify 
the slug, except the locality ; but they overlook the peculiar oliva- 
ceous color. British Museum slugs are not permitted to be dis- 
sected, and I gave the best account of the creature I could under 
the circumstances, It is to californicus much what Parmacella var. 
olivacea is to P. maculata, or Anadenus schlagintweiti to A. altivagus. 
Whether it is a good species or only a color variety cannot at pres- 
ent be determined, but at least it will be easily recognizable. 
Prop hysaon. 
In their introductory remarks, our authors allude to the difficulty 
of identifying West Coast slugs. I believe this difficulty is by no 
means a serious one, if one is familiar with the literature, and will 
exclude certain forms which are probably not distinct. The follow- 
ing table may help to separate the recognized species of Prophy- 
saon :— 
(1.) Epiphallus stout, sausage-shaped. A pale dorsal stripe. 
a. Ochreous species,. . . . . . P. pacificwm (inel. flavum). 
b. Grayish species, . . . . P. andersoni (incl. hemphilli). 
(2). Epiphallus banana-shaped, but tapering at the end. No pale 
dorsal stripe, . . P. cerulewm (Epiphallus rather slender, 
flattish, tapering, somewhat curved. Shell 2 mm. long, 
narrow, white, shiny), 
(3). Epiphallus slender, gradually tapering to a point. Body with 
a blackish dorsal band, 
