8(5 PPP. KKi'ouT OF pr;<>(;r:i<<. jamks; hall. 



EXPLANATIONS OF PLATES. 



PLATE III. 



EURYPTKRUS BeECHERI. 



Page SO. 



Fig. 1. Dorsal view of rlie si:)ecimen described, showing 

 the form of the body, the number, size, and orna- 

 mentation of the segments, and also a portion of 

 the large swimming appendages. 

 Chemung group. Warren., Pa. 



PLATE IV. 



EURYPTERUS MaNSFIELDI. 



Page 32. 



Fig. 1. The head and first abdominal segment, with the 

 palpi and other appendages attached. A j^ortion 

 of the segment and lower part of the carapace is 

 removed showing the median appendage of the 

 thoracic plate. 



Fig. 2. A small individual, enlarged to three diameters. 

 The palpi of the right side and telson are restored 

 from other specimens. The lateral processes of the 

 segments are not preserved. 



Fig. 3. A si:)ecimen of the natural size, represented on a 

 block of shale and showing the ferns and other 

 plant remains Avith which it is associated. 



Fig. 4. The fourth palpus of the right side enlarged to two 

 diameters, showing the form and surface ornament- 

 ation. 



Fig. 5. The second or third palpus from the right side, 

 enlarged to two diameters. 



Fig. 6. The last two joints of the large swimming foot, 

 enlarged to two diameters. 



