274 BULLETIN OF THE MUSEUM OF COMPAKATiVE ZOOLOGY. 



EXPLANATION OF THE PLATES. 



[Note. — A detailed description of the specimens figured in the plates will be found on pp. 257-264. 

 Unless otherwise statcJ, the specimen.^ are in the Museum of Comparative Zoology, and were obtained 

 from Iv. D. Atwood, Portland, Me. Those figured on Plate I. are reduced one half. Those figured on 

 Plate 11. are of the natural size.] 



Fig. 



17. 



(From Mus. Peabody Acad. Science, Salem, Mass. 

 Homarus Americanus, left chela. 



PLATE IL 



Fig. 1. Homarus Amerimnus, dactylus of right chela. 

 " 2. " " one of the small chelipeds. 



" 3. " " left chela. 



" 4. " " dactylus of right chela. 



•' 5. Callinectes hastalus, left chela. 



(From Chesapeake Bay; coll. Dr. S. F. Clarke.) 



" 6. Homarus Americanus, right cheliped. 



7. «« " left chela. 



•' 8. CallinccUs hastalus, left lateral iiart of the carapace with branched spine. 



(Coll. M. ('. Z.) 



" 9. Hmnarus Americanus, right chela. 



