MUSEUM OF COMPARATIVE ZOOLOGY. 



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jequituberculata. The specific representation on both sides of the 

 Isthmus of Panama is becoming every day, as far as Echinoderms are 

 concerned, more strikingly identical. Since the list given by Mr. Verrill, 

 several species have come to light, and the following comparative list 

 of species on both sides of the Isthmus, extending from Peru to the 

 Gulf of California on the Pacific, and including on the Eastern side 

 the Gulf of Mexico, Florida, the northern coast of South America, the 

 West Indies and Bahamas, may not be out of place. (I have examined 

 all the species here named.) This list would undoubtedly be greatly 

 increased by additional dredging. 



Eastern Fauna. 



[Caribbean.) 



Cidaris annulata Gray 

 Dorocidaris abyssicola A. Ac 

 Salenocidaris varispina A. Ac 

 Diadema antillarum Phil. 



Csenopedina cubensis A. Ac 

 Echinocidaris punctulata Desml. 

 Podocidaris sculpta A. Ac 

 Echinometra Michelini Des. 

 viridis A. Ag. 

 Echinus gracilis A. Ag. 

 " Plemingii Ball. 

 Genocidaris maculata A. Ag. 

 Trigonocidaris albida A. Ac 



Lyteclrinus variegatas A. Ag. 



Tripncustes ventricosus Ac 

 Clypeaster rosaceus Lam. 

 Stolonoclypus prostratus Ag . 



Ravenellii A. Ac 

 Mellita testudinata Kl. 



" hexapora Ag. 

 Encope Michelini Ag. 



" emarginata Ac 



Echinoneus semilunaris Lam. 

 Echinolampas caratomoides A. Ac 



Western Fauna. 



[Panamic.) 

 Cidaris Thouarsii Val. 



Diadema mexicanum A. Ag. 

 Astropyga venusta Ver. 



Echinocidaris stellata Ag. 



Echinometra Van Brunti A. Ac 

 rupicola A. Ag. 



Toxocidaris mexicana A. Ac 

 Lytechinus semituberculatus A. Ac 



Psammechinus pictus Ver. is the young. 

 Boletia rosea A. Ag. 

 Tripneustes depressus A. Ac 



Stolonoclypus rotundus A. Ag. 

 Mellita longifissa Mich. 



" pacifica Ver. 

 Encope grandis Ac 



" micropora Ag. 

 Echinoglycus Stokesi Gray. 



