200 



NEW YORK STATE MUSEUM 



- 



ones on either side; linear interspaces; sharply defined fold of 

 brachial valve, with plications almost obsolete. 



Found only in the Manlius limestone of North Buffalo and Will- 

 iamsville. Not common. 



Spirifer (Delthyris) sulcatus Hall (Fig. 120) (1852. Pal. N. Y. 



2:261, pi. 54) 



Distinguishing characters. Near- 

 ly equal valves; deep mesial 

 sinus ; four or more plications on 

 either side, with wide inter- 

 spaces; fine radiating striae 

 crossing plications and inter- 



suicatus with striae s P aces ; vel 7 coarse > lamellose, 

 subequally spaced concentric 



growth lines which interrupt the radiating striae. 



Found rarely in the Clinton lenses and the lower Rochester shale; 



more common in the Bryozoa beds at Niagara. Also at Lockport 



and elsewhere (Hall). 



Fig. 120 Spirifer (Delthyris) 

 enlarged 



Genus homoeospira Hall & Clarke 



[Ety.: 6/j.oios, like; a-sipa, spire] 



(1893. Pal. N. Y. v. 8, pt 2, p. 112) 



Shell rostrate, radially plicate, and with a short curved hinge line; 

 apex truncated by a circular pedicle opening. Spirals spiriferoid, 

 with from six to nine volutions and a V-shaped jugum. A linear 

 cardinal process separates the crural plates. 



Homoeospira apriniformis Hall (Fig. 121). 

 Atrypa aprinis Hall (1852. Pal. N. Y. 

 2:280, pi. 57) 



Distinguishing characters. Small, roundish, 

 oval, scarcely longer than wide; nearly equally convex valves; non- 

 sinuate front, numerous simple rounded plications; fine concentric 

 striae. 



Found in the Rochester shale at Lockport (Hall). Probably also 

 at Niagara. 



Fig. 121 Homoeospira aprini- 

 formis 



