A preliminary notice of the Sea-urchins collected on the Hassler Expedi- 

 tion was given in the Bulletin of the Museum, Vol. III. p. 187, January, 

 1873. The more interesting species are here described in detail, with figures 

 of those species which are not found in the Revision of the Echini, and which 

 complement the generic representations. The material collected has enabled 

 me to make corrections and additions to our knowledge of several of the 

 species of Echini, and many points interesting for the geographical distribu- 

 tion of the order have been added. 



At a depth of one hundred fathoms, off the Barbadoes, a large number of 

 species of Echini were dredged, showing that the deep-sea fauna character- 

 istic of the Pourtales Plateau, in the Straits of Florida, extends as far south 

 as the Barbadoes. The following list of the Echini fauna of that point will 

 prove interesting. The species collected at a depth of one hundred fathoms 

 were, 



Dorocidaris hystrix, Asthenosoma hystrix, 



Salenia varispina, Coelopleurus floridanus, 



Hemipedina cubensis, Temnechinus maculatus, 



Trigonocidaris albida, Echinus gracilis, 



Clypeaster subdepressus, Mellita hexapora, 



Echinocyamus pusillus, Echinolampas depressa, 



Paleopneustes cristatus, Meoma ventricosa, 



Metalia grandis, Agassizia excentrica. 



