THE NAUTILUS. 43 
ern New Jersey. As Say remarks, it is found “crawling on the 
dead leaves which have fallen to the bottom of the water.” 
I have learned by the examination of numerous specimens, that 
the operculum is multispiral, and the species will, therefore, be trans- 
ferred to the genus Lyogyrus of Gill. This character will readily 
separate the shell from small forms of Ammnicola. 
Amnicola missouriensis n. sp. 
One of the forms labelled “ Amnicola grana” in the collection of 
the Academy proves to be a new and very distinct species, which 
may be described as follows: 
Shell minute, imperforate, obliquely ovate, light brown ; surface 
smooth except for slight growth-lines; composed of 53 very con- 
vex whorls separated by unusually deep sutures ; apex obtuse, often 
eroded ; the last whorl! shortly defiexed in front in adult specimens. 
Aperture rotund-ovate, being slightly narrowed above, but not 
angular there; not modified in form by the preceding whorl ; 
inoderately oblique ; peristome continuous, not closely appressed at 
the upper left side; columellar margin calloused within, thick. Alt. 
1-7, diam. 1:5 mm.: length of aperture 0°8 mm. 
Carter County, Missouri (John Wolf). 
Much smaller than Bythinella Aldrichi Call, shorter, with thick 
and heavy columellar lip. 
Amnicola Walkeri n. sp. 
Shell thin, narrowly umbilicate, conic, shaped like Lyogyrus 
Brownti Carpenter ; slightly yellowish corneous ; thin, smooth, with 
faint growth-lines. Whorls 4, very convex, separated by deeply 
constricting sutures, the last whorl rounded below; apex obtuse. 
Aperture oblique, rather smal], mainly basal, a little longer than 
wide, but nearly circular, the inner margin a trifle straightened 
above ; peristome continuous, in contact with the preceding whorl 
for an extremely short distance above. Operculum and dentition 
Amnicoloid. 
Alt. 3, diam. 2; length of aperture 14, width 14 mm. 
Alt. 23, diam. 24; length of aperture 1:08, width 1 mm. 
Lake Michigan at High Island Harbor, Beaver Is., at 10 meters 
depth ; Reed’s Lake, Grand Rapids, Mich.; River Rouge, Wayne 
Co., Mich. ; the types from the first locality mentioned. 
This species has been under examination by Mr. Bryant Walker 
and myself for some months. It was thought at one time to be Say’s 
