94 A MANUAL OF AMERICAN LAND SHELLS. 



veloped triangular cutting points. The laterals are like the centrals, 

 but asymmetrical by the suppression of the inner lower lateral expan- . 

 sion to the base of attachment, and the inner side cutting point, the \ 

 inner side cusps being still subobsolete. The change from lateral to 

 marginal teeth is shown in b and c, the inner cusps and cutting point 

 being greatly developed, and the base of attachment is still narrower 

 than in the first laterals. The marginals are shown in d and e. They 

 are about as high as wide, the reflection equals the base of attachment 

 and bears an extremely long, blunt, stout, oblique cutting point, with 

 a side spur upon the last, in the extreme marginals developed into a 

 short, stout, side cutting point. The cutting point of the marginals 

 by its great development forms the chief characteristic of the mem- 

 brane ; it is well shown in i)roflle.* There were 22 perfect laterals in 

 this specimen. The figure referred to above shows only 12 laterals, 

 with 113 rows of 56-1-56 teeth each. 



I have examined one specimen of Ariolimax niger, J. G. Cooper, pre- 

 served in spirit, belonging to the State collection of California, labeled 

 and presented by Dr. Cooper, and in all respects an authentic type. 

 Agreeing with this type 1 have other specimens from various Califor- 

 nia localities, so that I believe the species to be well established and 

 generally distributed along the coast of California. 



From the Museum of Comparative Zoology at Cambridge, Mr. An- 

 thony has sent me a specimen, long j) reserved in alcohol, marked from 

 San Mateo, California. For reasons given below, I am inclined to con- 

 sider this the form described by Dr. Cooper as A. Californicus. I have 

 had the opportunity of examining another specimen of this form, re- 

 ceived from Dr. Stearns, who collected it near San Francisco. And 

 recently I have examined specimens received from Dr. Cooper. 



From Mr. Henry Hemphill I have received a specimen from San 

 Mateo County, California, which presents most decided specific difter- 

 ences from the last-mentioned form, especially in its genitalia. Hav- 

 ing considered the last-meutioned form as A. Californicus, I was forced 

 to consider this as ^. Co/wm&iam/s, the only remaining described species. 

 I had not at that time compared it with specimens from more northern 

 regions, whence the species was originally described, but I have now 



* In only one instance have I seen marginal teeth as in my figure (of Plate V, Fig. F, 

 d). In all other specimens examined the marginals are as figured in Plate V, Fig. E, e, 

 with one long cusp and one obsolete side cusp. 



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