LATE CENOZOIC GASTROPODS 



9 



ly impressed sutures, a smaller, rounder aper- 

 ture, the lip of which is usually thickened 

 within. There are six full whorls in adult 

 individuals." 



Length, 4.25; diameter, 2.25; aperture 

 length, 1.25; width, 1.0 mm. Holotype. 

 (Baker's measurements.) 



Type locality: Marl deposit near Morris, 

 Grundy County, Illinois. 



Collector: F. C. Baker, 1921. 



Age designation: Pleistocene, Late Wis- 

 consin. 



Remarks: The ISGS collection contains 

 two paratypes, no. P927. Baker later (Wis- 

 consin Geol. and Nat. Hist. Surv. Bull. 70, 

 pt. I, p. 112 ) raised gelida to a full species; 

 the collection contains many lots from differ- 

 ent localities, identified by Baker as A. gelida. 



Amnicola precursor Baker, 1928 

 Plate 1, figure 8 



Holotype: Cat. no. Z22508, ISGS. 



Original description: Wisconsin Geol. and 

 Nat. Hist. Survey Bull. 70, p. 116, pi. VII, 

 fig. 5; text fig. 47 (6-9); 1928. 



"Shell: Small, conic, rather thick, surface 

 with rather coarse, close-set growth lines; 

 spire broadly conic, elevated, much longer 

 than aperture; whorls 5%, very convex, reg- 

 ularly but not rapidly increasing in diam- 

 eter ; sutures very deeply impressed ; apex ob- 

 tuse, flattened, the nuclear whorl small, 

 rounded, finely granular in texture, slightly 

 elevated above second whorl; aperture al- 

 most circular, slightly angled above; peris- 

 tome continuous; base rounded, umbilicus 

 wide and deep." 



Length, 3.0; width, 2.3; aperture length, 

 1.4; width, 1.2 mm. Type. Female? (Bak- 

 er's measurements.) 



Type locality: Green Lake, Green Lake 

 County, Wisconsin, off Sherwood Forest 

 Hotel, below seven meters of mud. 



Collector: Wisconsin Geological and Nat- 

 ural History Survey party, July 7, 1921. 



Age designation: Pleistocene, Late Wis- 

 consin. 



Remarks: The ISGS collection contains 

 three paratypes, bearing the same number as 



the type, as well as many other lots identified 

 by Baker as A. precursor. 



Amnicola winkleyi leightoni Baker, 

 1920 



Amnicola leightoni Baker 



Plate 1, figure 10 



Holotype: Cat. no. P598, ISGS. 



Original description: Nautilus, v. 33, p. 

 125, April 1920. 



"Shell differing from A. winkleyi in be- 

 ing larger, heavier, wider in proportion to its 

 height, the body whorl being more globose 

 than in the typical form; there are 4^4 

 whorls, the upper part of which is somewhat 

 flat-sided just below the suture; this is espe- 

 cially marked on the last whorl of some in- 

 dividuals; the spire whorls are rounded and 

 the sutures deeply impressed ; the first whorl 

 is flatter than in winkleyi) the umbilicus is 

 wider and deeper and the aperture is wider 

 in proportion to its height than in winkleyi. 

 Length, 5.0; diameter, 3.7; length of aper- 

 ture, 2.5 ; width, 2.0 mm." Holotype. 



Type locality: Rush Lake, Logan County, 

 Ohio. 



Collector: M. M. Leighton, 1919. 



Age designation: Pleistocene, Late Wis- 

 consin. 



Remarks: The ISGS collection contains 

 two specimens labeled "paratypes," cat. no. 

 P599, and ten examples labeled "cotypes," 

 cat. no. P600. In 1921, Baker (Nautilus, v. 

 35, p. 23) raised leightoni to the rank of full 

 species. Many lots in the collection bear this 

 designation. 



BULIMUS TENTACULATUS MAGNALACUSTRIS 



Baker, 1928 

 Plate 4, figure 4 



Paratypes: Cat. no. Z22506 and P2819, 

 ISGS. 



Original description: Wisconsin Geol. and 

 Nat. Hist. Survey Bull. 70, pt. 1, p. 81, pi. 

 IV, figs. 22-23, 26-31, 1928. 



"Globosely turbinated, rather thick, trans- 

 parent to opaque ; color ranging from yellow- 

 ish to greenish, with thin brownish epider- 

 mis; surface shining, lines of growth fine, 



