NO. lO NEW BRACK lOPODS COOPER 5 



Figs. 3, 5. Ventral and dorsal views respectively of a young individual show- 

 ing mucronate cardinal extremities and intercalated median rib, 

 X 4. Paratype, U.S.N.M. no. 431003a. 



Fig. 4. Ventral view of a somewhat larger individual than the preceding 

 (431003a). The cardinal extremities are much less angular and 

 the proportion of width to length has decreased, X 4. Paratype, 

 U.S.N.M. no. 431003b. 



Figs. 6, 7. Young specimen in which median intercalated rib has not yet 

 developed, X 4. Paratype, U.S.N.M. no. 431003c. 



Fig. 8. Dorsal interior showing the lophophore, X 4- Paratype, U.S.N.M. 

 no. 431003d. 



Figs. 9, 10. Dorsal and ventral views respectively of the holotype, X 4- The 

 ventral valve shows the median intercalated rib, but this is not 

 represented on the dorsal valve. Note broad rounded costae. 



Fig. II. Ventral interior showing pedicle collar and strong median septum, 

 X 6. Paratype, U.S.N.M. no. 4310036. 



Fig. 12. Dorsal interior showing loop and its union with the floor of the valve, 

 X 6. Paratype, U.S.N.M. no. 4310036. 



