226 PANAMIC DEEP SEA ECHINI. 



The stations occupied off Havana, varying in depth from 120 to 400 

 fathoms off Morro Light, were all wonderfully rich in species not only of 

 Echini, but of Corals and Ophiurans. 



In my Report on the "Blake" Echini' I called attention to the inter- 

 esting comparisons to be made between the abyssal Echinid fauna of the 

 West Indian and of the Panamic regions when the material became avail- 

 able. The Echini collected by the "Albatross" Expedition of 1891^ in 

 the Panamic region comprise twenty-four species, only three of which 

 belong to the continental slopes ; the others are deep-sea types, such as 

 Porocidaris, Salenia, a new abyssal genus of Arbaciadae, Dermatodiadema, 

 Phormosoma, three Pourtalesia3 : Pourtalesia, Plexechinus, and Echino- 

 crepis ; four species of Urechinidae belonging to Urechinus, Cystechinus, 

 Pilematechinus • two Paleopneustidas : Phrissocystis, and Homolampas ; and 

 among the Spatangime and Brissina, Aerope, Schizaster, Periaster, Bris- 

 sopsis, and Toxobrissus, all of which have abyssal representatives among 

 the West Indian Echinoidea. The discovery of these species only increases 

 the great similarity already known to exist between the littoral and conti- 

 nental species of the two sides of the Isthmus of Panama. 



I have given in the "Blake" Ecliini^ a Table showing the West Indian 

 species of Echini which have representatives in the Panamic area. This 

 Table is here reproduced with the addition of the bathymetrical range of 

 both the West Indian and Panamic species as far as it is known. I have 

 not repeated the list of the nearest representatives in post-Cretaceous and 

 Cretaceous times, as but few additions have been made to the fossil species 

 of American Echini. The principal additions are found in Clark's Revision 

 of the Cretaceous Echinoidea of North America.* They consist in additions 

 to ray list of two species of Cretaceous Cidaris, of three species of Salenia 

 from the Cretaceous of Texas, of a species of Goniopygus, of Cyphosoma, and 

 of Psammechinus, also from Texas, of two species of Scutella and Echino- 

 brissus from Alabama and Texas, of three species of Cassidulus, of a Periaster, 

 of additional species of Ilemiaster, and a Linthia. With the exception of 

 Salenia, Goniopygus, Periaster, and Linthia, no genera not included in my 

 list have been added to the Table. Other interesting additions have also been 

 made by Professor Gregory, who has described two species of fossil Echini 



» Mem. M. C. Z. 1883. X, No. 1, p. 82. 



2 Bull. M. C. Z. 1898, XXXII. No. 5, p. 71. 



« " Hlake" Echini, p. 85. 



* W. B. Clark, Johns Hopkins University Circulars, No. 86, 1891. 



