THE NAUTILUS. 77 



"Ariolirnax coiumbian.u#, 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 cal. 11, of columb. 13 mm.). Sole of cofumb. 

 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 ocbreous, columb. has black mot- 

 tling on body (v. maculatus Ckll.) ; calif, has similar black marbling 

 on body, but mantle, instead of being unicolor, has a large black 

 spot, diam. 6 mm., over place of shell (v. maculatus, nov.). This 

 spot on mantle is in fig. of columb. mac. in Binney, PI. vi, f. A." 

 (Ckll. MSS.). 



Ario Umax 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. inaculata, or Anademis schlagintweitito 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. 



Prophysaon. 



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 Prop hy- 

 saon : 



(1.) Epiphallus stout, sausage-shaped. A pale dorsal stripe. 



a. Ochreous species, P. padficum (mcl./ai>w?/<). 



b. Grayish species, .... P. andersoni (incl. hemphilli). 

 (2). Epiphallus banana-shaped, but tapering at the end. No pale 



dorsal stripe, . . P. cceruleiim (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. 



