77% 



NORTH AMERICAN INDEX FOSSILS. 



563. S. interstriatus (Heilprin). (Fig. 1 135.) Eocenic. 



Whorls round ; suture moderately deep ; ribs simple and con- 

 tinuous from suture to suture, about their width apart; spirals 



FlG. 1 1 34. Lathyrus Jlorida 

 nus,\i.i3. (After Dall.) 



Fig. 1 1 35. Streptolathyrus interstriatus, en- 

 larged. (Md. Survey.) 



numerous ; compound columella with one strong oblique plication ; 

 lirse of outer lip rather strong. 



Pamunkey formation of Maryland and Virginia; Chickasawan 

 (Lignitic) of Alabama. 



CLXVII. Pseudolathyrus Bellardi. 



Shell fusiform, with protoconch of Fahifusus type. Whorls 

 mostly angular with ribs and spirals, the former often becoming 

 obsolete except on angle. Canal straight, not twisted, non-umbili- 

 cate; columella plicate in adult. Eocenic-Pliocenic. 

 564. P. tortilis (Whitfield). (Fig. 11 36.) Eocenic. 



Whorls angulated; shoulder flat; ribs weak, far apart, scarcely 

 extending below angulation; embracing of whorls falls short of 

 angulation by half the shoulder width; contraction to canal grad- 

 ual; columella with two plicae, the upper one faint. Spirals com- 

 pound. 



Midwayan of Alabama, Georgia and Mississippi. 



CLXVIII. Lirofusus Conrad. 

 Short, thick-spired, fusoid shells with short, somewhat inflated 

 canal, pyriform aperture, and lirate outer lip ; no columellar plica- 

 tions. Eocenic. 



