PLATE XXIX. 



ECHINOCAEIS PUNCTATA. 



See Plates 27 and 28. 

 Fig. 1. An enrolled individual of average size, having the carapace somewhat compressed, bul showing 

 the position of the optic spots (e), the number and disposition of the nodes, a well-defined nuchal 

 furrow and the tubercles along the posterior portion of the hinge-line. A single caudal spine 

 is seen projecting from beneath the anterior portion of the carapace. 

 Fig. 2. Profile view of the same, showing a portion of the enrolled abdomen. 



Hamilton group. Pratt's /•'tills. Onondaga county. 

 Fig. 3. A nearly entire individual, showing the valves of the carapace fully expanded and the six abdom- 

 inal somites, which are detached from the carapace. The caudal parts are missing and are 

 restored in outline. 



Hamilton group. Pratt's Falls, Onondaga county. 

 Pig. 4. A specimen showing the post-abdomen and a portion of the internal surface of the last two somites 

 of the abdomen. 



Hamilton group. Pratt's Falls. Onondaga oounty. 

 Pig. 5. An expanded carapace covered with individuals of Discina media, Hall, not an infrequent mode of 

 occurrence at this locality. 



Hamilton group Pratt's Falls, Onondaga county. 

 Pig. fi. A portion of the surface of the carapace represented in plate 28, fig. 2, enlarged to two diameters 

 to show the character of the ornamentation between the carina and the ventral margin. The 

 specimen is a cast of the internal surface, and shows the strong punctse which become still more 

 conspicuous near the lower edge of the carina, and the elevated, undulating lines radiating from 

 the carina. Upon the upper surface of the test the ornamentation is distinctly pustulose and 

 the radiating lines are scarcely visible. 



Hamilton group. Fahius, Onondaga county. 

 Fig. 7. An imperfect specimen, showing the internal surface of the left valve of the largest carapace 

 observed. In the cephalic region there lies a single large mandible which shows no denticles, 

 but bears a conspicuous manubrium. The posterior margin of the valve bears three strong 

 tubercle-, a featuife usually but faintly developed in smaller individuals. 

 Hamilton group. Vinegar Brook Grlen, Cayuga Lake. 

 Fig. 8. A large right valve, showing normal proportions and the position of the optic spot, but wanting 

 the elevated lines on the ventral surface and the posterior marginal tubercles. This is the type 

 specimen of Ceratiocaris > punctata, Hall, and was originally figured with a conspicuous node 

 near the posterior extremity of the hinge-line; this, however, has proven to be a portion of the 

 matrix. 



Hamilton group. Cayuga Lake. 



EOHINOOARIS PUSTULOSA. 

 Page 178. 

 Fig. 9. The type specimen ; a light valve showing the number and disposition of the nodes, the character 

 of the carina and the strong pustules upon the surface of the nodes. A portion of the cephalic 

 region is broken away and is restored in outline. 

 Pig. 10. The same, enlarged to two diameters. 



Erie shales. (Portage group.) Paine's Creek, Lake county, Ohio. 



