PLATE XXVII— Continued. 



Stylonurus (?) (Echinocaris?) Wrightianu*. 



Page 160. 



Pig. 7. Dorsal view of the type specimen of Equisetides TVriglitlanus, Dawson. The specimen consists 

 of two abdominal somites of this crustacean* preserved as an internal cast in sandstone and 

 showing tin; pustulose ornamentation, the conspicuous ridges along the posterior margin of 

 each somite and the character of the articulation between the somites. On the anterior surface 

 of the last somite several longitudinal impressions are seen, apparently made by the long 

 posterior spines of the preceding somite. 



Fig. 8. Side view of the same specimen, showing the character of the articulation, the strong marginal 

 ridges and the smooth ventral surface. The specimen has been slightly flattened, vertically 

 making the convexity of the somites somewhat less than it should normally be. 



Fig. 9. An enlargement of the surface to show the character of the ornamentation. 

 Portage group. Italy, Yates county. 



Echinocaris punctata. 



Page 166. 

 See Plates 28 and 29. 

 Fig. 10. An enlargement of the surface of an abdominal somite from the specimen represented on plate 28, 

 tig. 4. Introduced for comparison with the preceding figure. 



Hamilton group. Ticltenor's Point, Canaitdaigua Lake. 



