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 Amnicola. 



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 3? very con- 

 vex whorls separated by unusually deep sutures ; apex obtuse, often 

 eroded ; the last whorl shortly deflexed in front in adult specimens. 

 Aperture rotund-ovate, being slightly narrowed above, but not 

 angular there ; not modified in form by the preceding whorl ; 

 moderately oblique ; peristome continuous, not closely appressed at 

 the upper left side; columellar margin calloused within, thick. Alt. 

 1'7, diam. 1*3 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 Lyogym* 

 Brownii 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 small, 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 1-j, width H mm. 



Alt. 2J, diam. 2 ; 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 



