150 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



or plate-like, and are not separated by darker-colored anastomosing lines, the 

 intervening furrows being of the same color as the general surface. It does not 

 secrete a milky mucus at every part of the surface when touched. Like that 

 species, it is active in its motions, and suspends itself by a thread of mucus. 

 In its genitalia it differs widely in wanting the curious trifurcate gland to the 

 penis sac found in agreslis, and in the shape of the genital bladder and length 

 of its duct. 



This species appears to be common to all the northern parts of the United 

 States. It is found under decaying wood in the forests and in open pastures, 

 and under stones at roadsides. From its wide distribution it would seem to 

 be indigenous. 



Its testaceous rudiment is minute and delicate in proportion to the small size 

 of the animal. 



Mr. Gwyn Jeffreys (Ann. Mag. Nat. Hist. 1872, p. 245) suggests the iden- 

 tity of campestris with Icevis, Mull., a European species. Lehmann's figure of 

 the genitalia and dentition of that species show that there is no foundation for 

 any such theory. 



Jaw as usual in the genus. Ends pointed, recurved ; centre with a trans- 

 verse, strong line of reinforcement ; median projection sharp. 



Lingual membrane (PI. I. Fig. I). One specimen has 40 — 1 — 40 teeth, with 

 18 perfect laterals. Another gives 36 — 1 — 36, with 11 perfect laterals. The 

 centrals and laterals are of the same type as described above in L. agrestis, 

 excepting that there is no peculiar inner side cutting point to the first laterals. 

 About half of the marginals are bifid. I find great difficulty, however, in de- 

 tecting any bifurcation on the extreme marginals. 



As stated above, Heynemann's figure of the dentition of L. Weinlandi could 

 not have been drawn from this species. I have no information in regard to L. 

 Weinlandi other than what I find in Malak. Blatt. X. 212, PI. III. Fig. 1. 

 Judging from the dentition alone, I should hardly consider it distinct from 

 agrestis, excepting in its wanting the peculiar inner side cutting point to its 

 first laterals. 



The California form noticed by Dr. Cooper as var. occidentalis is known to 

 me by a single specimen received living from him. In external appearance, 

 genitalia, and jaw it cannot be distinguished from the Eastern form. Its lin- 

 gual membrane (PI. I. Fig. L) has 35 — 1 — 35 teeth, of which 13 are laterals. 

 The inner as well as outer laterals show occasionally the side spur, thus more 

 nearly resembling those of inontanus than campestris. I am inclined to believe 

 future study will prove all three forms identical, notwithstanding these slight 

 differences in detail of dentition. 



Liraax Hewstoni, J. G. Cooper. 



Similar to L. Sowerbii (of England), the back being strongly carinate even 

 when fully extended, and higher than the front of the body ; mantle granulate- 



