PLATE XXX. 
Fiff- 
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Echinocaris socialis. 
Page 174. 
1. A very young, entire individual representing the earliest stage of growth observed. 
Chemung group. Warren, Wart'mi county, Fennsylvania. 
2. A young individual in which the abdomen is bent dorsally. 
Chemung group. Warren, Wai'ren county, Pennsylvania. 
3. An example with the valves expanded and the abdomen protruding from tlie anterior margin of 
the carapace. 
Chemung group. Warren, Warren county, Pennsylvania. 
4. An individual with the valves expanded and the abdomen closely curved around the posterior 
margin of the left valve. 
Chemung group. Warren, Warren county, Pennsylvania. 
5. The expanded valves of a larger individual. 
Chemung group. Warren, Wan'en county, Pennsylvania. 
6. A lai-ger, expanded carapace somewhat enlarged, showing more distinctly the character of the 
surface oi’namentation. 
Chemung group. Warren, Warren county, Pennsylvania. 
7. A nearly entire mature example, enlarged to two diameters, showing the arrangement of the 
spinules on the abdominal somites, and the very slender caudal spines. The anterior portion 
of the carapace is somewhat restored in the drawing. 
Chemung gi-oup. Warren, iVarren county, Pennsylvania. 
8. The I'ight valve of a large carapace with the abdomen attached. 
Chemung gi'oup. iVarren, Wairen county, Pennsylvania. 
9. A fragment of shale preserving the remains of fifteen immature individuals, nine of which are 
visible on the side represented in the figure. 
Chemung group. Warren, Warren county, Pennsylvania. 
10. An enlargement to three diametei-s of a xiortion of the xwstero-lateral surface of the right valve, 
showing the crenulated summit of the lower cai-ina and the tuberculous character of the 
upjier Carina. 
Chemung grouj). Warren, Warren county, Panmylvania. 
11. Two abdominal segments, enlarged to two diametei'S, showing the bases of the sxiinnles The 
nodes across the middle of each segment ar sf)iniform when j)ei-fectly xireserved. 
Chemung groux). Warren, Warren county, Pennsylvania. 
12. Three abdominal segments and the post-abdomen of a large individual. 
Chemung groux-). Warren, Warren county, Pennsylvania. 
Mandibles of Phyllocarida. 
Page 170. 
13. A large specimen, natural size, showing the molar-like axipearance of all the denticles excex^t the 
Xiosterior one, which is sha.rxi and comxiosed of a single cusxn 
Hamilton grouxi. Pratt’s Falls, Onondaga county. 
14. A specimen preserving the “manubrium” and showing the number and character of the cusx)s. 
Hamilton group. Pratts Falls, Onondaga county. 
15. The crown of a large example. 
Hamilton group. Pratts Falls, Onondaga county. 
16. A small example, showing but five cusps. In this specimen the basal poi-tion of the mandible is 
not distinctly separated from the crown. 
Hamilton groux). Pratts Falls, Onondaga county. 
17. A somewhat larger specimen, with a strong terminal cusp. 
Hamilton group. Pratts Falls, Onondaga county. 
