NATURAL SCIENCES OF PHILADELPHIA. 143 



ON NEW CALIFORNIAN PULMONATA, ETC. 

 BY J. G. COOPER, M.D. 



ALEXIA SETIFER. Cp. n. s. PI. 3, fig. A. 1 to 6. 



Sp. en. Alexia "A. myosotis" persimilis, seel testa, juniore retis bre- 

 vissimis decidnis munita, liuea spirali ante sutura sitis. Var. tenuis, 

 elongata, pallida. 



Lat. 0.08 ad 0.14, alt. 0.30 ad 0.40 partes cent, pollici. 



Shell very similar to A. myosotis (of the northern Atlantic 

 States), but the young provided with short deciduous bristles, 

 arranged in a spiral line just in front of the suture. 



Form varying from ovate to lanceolate, translucent, smooth, 

 pale to dark corneous, with a purple tinge, often marked with nu- 

 merous longitudinal paler stripes; apex short, or rather length- 

 ened and subacute ; suture usually distinct, whorls six or seven, 

 the nuclear three or four, very narrow, and nearly alike, with the 

 apex inverted or planorvoid ; the last elliptic-ovate, and forming 

 nearly three-fourths of the total length ; aperture nearly two- 

 thirds of total length ; peristome thickened and projecting hori- 

 zontally, especially in front, appressed to columella, leaving a 

 slight umbilical fissure open, then blending with a strong plait 

 which winds obliquety inward ; parietal wall with a white trans- 

 verse flat denticle near its middle, and usually a small tubercle 

 above it, making the mouth three-toothed on the inner side. 



Young shell showing the bristles on about three whorls, the 

 first two or three being without them, and losing them by wearing 

 off after attaining half its growth. 



The variety tenuis is slender, elongated, shell usually thinner 

 and paler, sometimes amber-3 T ellow. Many of the more robust 

 form are, however, fully as thin and pale. 



Animal yellowish-white, translucent ; eyes black ; tentacles trans- 

 parent, faintly wrinkled, muzzle strongly wrinkled transversely. 



This species seems chiefly characterized by the bristles of the 

 young shell, but these may exist in some other species, being easily 

 overlooked, or rubbed off in cleaning the shell, which is often 

 covered with adhesive mud. 



The usual form of the adult differs much from the figure given 

 by Binney of u A. myosotis" more resembling other European 



