148 PROCEEDINGS OF THE ACADEMY OF 



Dr. Gould mentions a "small specimen uniformly slate color" 

 (probabty from alcohol), which indicates that this is also found in 

 Oregon. A very young one from east of S. F. Bay has the shield 

 and back brownish with small irregular black spots, and no cari- 

 nation perceptible as it is in the yellow species, which shows it 

 stronger in the young than the adult. The dorsal grooves agree- 

 ing with those of the Oregon form suggested that it was only a 

 southern dwarfed variety of that, which is often mottled with 

 blackish ; but Dr. Gould's specimen was also small, and may in- 

 deed have been collected in California. Here I find none inter- 

 mediate between this and the yellow variet}^. The color and dorsal 

 grooves agreeing with Limax Hewstoni also suggested hybridity, 

 but I have never found this in the same localities with that species. 

 We thus have three very distinct species often equally black, but 

 the onl} r common cause I can guess for this similarity is possibty 

 more nocturnal habits than in the others. The comparative 

 rarity of this form may be a consequence of more thorough con- 

 cealment in the daj'time. I found them copulating in December, 

 and the young was found in February probably recently hatched. 



ARION? ANDERSONII. Cp. n. s. PI. 3, fig. F. 1, 2, 3, 4, 5. 



Sp. en. A, " Arioni foliato" similis, sed niulto minor, spiraculo prope 

 medio clypei forte granulato rugosi, testa interna valida ; cauda acuta. 

 Foramen generativuni ut in Ariolimax et Limax Ilewstoni situm. 



Long. ii. et dim. poll. ; lat. dioci motivi plus quam dimidium alt. cor- 

 poris. 



Similar to " Arionfoliolatus," but much smaller, the spiracle close 

 to middle of shield, which is strongly granulae-rugose ; a strong 

 internal shell ; tail acute. Length two and a half inches ; breadth 

 of locomotive disk more than half the height of body. Form 

 slender, gradually tapering from the shield backwards to an acute 

 point; shield large, covering one-third of back, distinctly granular, 

 the spiracle not perceptibly anterior to middle, except when the 

 animal is fully extended ; upper tentacles little over one-fifth of 

 the length of mantle, which is free in front nearly as far back as 

 the spiracle, and a narrow edge free behind ; dorsal furrows about 

 18, distinctly darker colored; foot slightly projecting at sides, the 

 lateral bands distinctly separated beneath and marked by muscu- 

 lar fibres running obliquely backward and outward on the under 

 surface. 



