GASTROPODA— LOXONEMATIDM. 



695 



287. L. rugosum M. and W. (Fig. 995.) Carbonic. 

 Like the preceding, but the striae stronger, scarcely curved and 



almost rib-like, about 18 to a whorl. 



Coal measures of Illinois, New Mexico, etc. 



288. L. scitulum M. and W. (Fig. 996.) Carbonic. 



Fig. 996. Loxonema scitulum. (After 

 Meek and Worthen, Pal. 111., II. ) 



Fig. 997. Loxonema ( Slreptaxis)- 

 whitfieldi, X 4> with protoconch and 

 body whorl further enlarged. 



Smaller than preceding, suture more deeply impressed, costae 

 about hA to a whorl, obsolete on base of body whorl. 

 Coal measures of Illinois, Iowa, and Missouri. 



289. L. (Streptaxis) whitfieldi Meek. (Fig. 997.) Carbonic. 

 Minute, slender, loose-coiled, with 8 or 9 long slender whorls 



and deep suture, aperture oval; surface striae fine, numerous, and 

 doubly curved ; apex erect. 



Coal measures of Illinois and Iowa (roof of Danville coal). 



LXXXII. Aclisina de Koninck. 

 Like Loxonema, but with spiral lines on the whorls, the vertical 

 sigmoid lines weak. Carbonic. 



290. A. robusta Stevens. (Fig. 998.) Carbonic. 



Fig. 998. Aclisina robusta, X 2 X> 

 and body whorl much enlarged. (After 

 Meek and Worthen, 111. Geol., V.) 



Fig. 999. Aclisina stevensana, com- 

 plete individual, X 3; body whorl greatly 

 enlarged. (After Meek and Worthen, 

 111. Pal., II.) 



Minute (5 mm. long), rather broad-spired, round-whorled, with 

 numerous fine revolving lines and sigmoid lines of growth. 



