INVERTEBRATES. 367 



which are fine, rather regular, and scarcely deflected from 

 their course by the presence of the nodes. Length, measuring 

 from the most extended part of the aperture obliquely to the 

 apex of the spire, 1.08 inches; breadth, 0.98 inch; apical angle 

 convex, divergence about 100°. 



Locality and position : St. Clair county, Illinois ; Lower Coal Measures. 



Naticopsis nodosa var. Hollidayi, M. and W. 



PL 31, fig. 3 a, 3 6. 



Naticopsis Holidayi, Meek and AVorthen. October, 1860. Proceed. Acad. Nat. Sci., 

 Philad., p. 463. 



This agrees so nearly with the last, that we doubt now, the propriety of 

 regarding it as a distinct species. It only differs in having its columella more 

 broadly flattened, and its nodes more numerous, and more crowded. In the 

 figures of both of these forms, the engraver has made the nodes to appear to 

 arise too abruptly from the surface of the shell. They are all more spreading at 

 the base. Length, 1.24 inches; breadth, 1.10 inches; apical angle nearly 

 regular, divergence 100°. 



Locality and position: Hodge's creek, Macoupin county, Illinois; Lower 

 Coal Measures. 



Genus MACROCHEILUS, Phillips. 



Syncn. — Buccinum (sp.), Sowerby and others; (not of Linnasus). 



Macrocheihcs, Phillips, 1841. Palaeozoic Fossils, p. 103; (not Kirby, 1838, 



genus Coleoptera). 

 Plectostylus, Conrad, 1842. Journal Acad. Nat. Sci., Philad., vol. viii, p. 275 ; 

 (not Beck, 1837). 



Shell subglobose or more or less elongate ; spire pointed at 

 the apex, and composed of several smooth, moderately convex 

 volutions; body whorl large; aperture ovate or subovate, rounded 

 and sometimes slightly effuse below and angular behind; colu- 

 mella imperforate ; outer lip thin, and without notch or sinus ; 

 inner lip thin or wanting above the middle of the aperture, 



