22 PPP. RKPOKT OF PROGRESS. C. E. BEECHER. 



Tropidocakis bicarinata, Beeclier. 



Page 16. 



Fig. 3. A carapace with the valve opened and the test 

 somewhat broken, showing the eye-tubercles and a 

 pair of longitudinal ridges on each valve. 

 " 4. The right valve of a smaller individual. 

 " 5. Two segments of the abdomen with a portion of 

 the telson attached, showing the form and orna- 

 mentation of the somites. 



Chemung group ; Warren^ Pa. 



Tropidocaris interrupta, Beecher. 



Page 18. 



Fig. 6. A right valve of this species showing the form and 

 ornamentation. 

 Chemung group ; Warren., Pa. 



Tropidocaris alternata, Beecher. 



Page 19. 

 Fig. 7. An imperfect left valve, preserving the longitudinal 

 ridges, and showing the tubercles and optic node 

 on the cephalic portion. 

 " 8. A fragment of a large left valve, bearing the im- 

 press of the plates of an echinoderm. 

 Waverly group ; Warren^ Pa. 



Mandibles. 



Page 9. 



Fig. 9. A specimen preserving the manubrium, and show- 

 ins the number and character of the denticles. 



" 10. The inner edge of a smaller example. 



" 11. The crown of a large specimen with the denticles 

 well-preserved and showing its arched and lunate 

 form. 

 • Hamilton group ; New YorTc. 



