SOME NEW BRACHIOPODS AND GASTROPODS 223 



Floydia concentrica multisinuata nov. var. 



Shell large and fairly thick except on the upper and outer parts 

 of the body volution, spire high, volutions somewhat angular, 

 particularly the body volution ; volutions four to six, suture strong 

 but not so deep as in the typical form. Aperture large ; columella 

 lip thick and somewhat flattened. Upper two-thirds or more of the 

 body volution, all or nearly all of the second, and apparently much 

 of the third volution marked by regular, deep folds or wrinkles 

 arching abruptly back and then deeply forward from the suture ; 

 surface of the volutions marked by rather to very fine lines of 

 growth. Folds of much finer and more pronouncedly delineated 

 character than in the typical species. 



This variety is the most distinct of the forms now placed in 

 Webster's Floydia, and is the farthest separated from the genus 

 Naticopsis. It differes from the typical Floydia concentrica in the 

 higher spire, the finer character of the shell. The holotype, as 

 illustrated, shows well the characteristics of the variety. 



I have found that Floydia concentrica Webster is more numerous 

 in the Rockford district and particularly at the brick pit than it is 

 at Hackberry Grove. I have found comparatively few at the latter 

 locality, while Naticopsis gigantea Hall and Whitfield seems more 

 prominent. 



Holotype: — Number 40, collection of C. L. Fenton. Pit of 

 Rockford Brick and Tile Company, Rockford, Iowa. Spirifer zone. 



EXPLANATION OF PLATE VI. 



Figs. 1-2. — Airypa reticularis alta. Lateral and anterior views of holotype. 

 Figs. 3-4. — Spirifer Whitneyi rockfordensis. Lateral and anterior view of 



holotype, posed to show fully the sinus development. 

 Figs. 5-6. — Spirifer Whitneyi productus. Anteriod and pedicle views of 



holotype. 

 Figs. 7-10. — Spirifer Whitneyi gradatus. 7, 8, 9,' lateral, anterior and 



pedicle views of three cotypes. 10, Posterior view of specimen shown 



in fig. 9. 

 Figs. 11-17. — Spirifer cyrtinaformis Helena. n, 12, 13, anterior, posterior, 



and lateral views of holotype. 14, enlarged outline of lateral view, 



showing beak development. 15, posterior view of a paratype. 16. 



enlarged lateral view of same, and 17 a tracing of the dorsal valve. 

 Figs. 18-22. — Strophonella reversa gravis. 18, 19, dorsal and lateral views of a 



regularly formed cotype. 20, 21, 22, dorsal, lateral, and ventral views 



of a heavy cotype. 



