194 BULLETIN OF. THE 
zaster proper, namely, of such species as Sch. canaliferus, Sch. fragilis, Sch. Phi- 
lippii, but has the outlines of Hemiaster, the fascioles of Periaster. It has but 
two genital openings. When brought up in the dredge, this species was of a 
dirty yellowish-brown color. 
In order to retain for the Challenger Echini the priority, I did not intend to 
figure or fully describe in this paper any of the species previously dredged by 
the Challenger. From apreliminary examination of the two specimens brought 
home by the Challenger, I had, without having denuded the test, referred 
them to Hemiaster. My mistake I discovered only too late, after the plates of 
this paper were printed. As the figures represent specimens of a much larger 
size than those of the Challenger, they will not duplicate those to be given 
for the Challenger Echini. 
In the vicinity of a thousand fathoms in depth and below it, we find in the 
Gulf of Mexico genera dredged by the Challenger in deep water in the Atlantic 
and Pacific, which appear to have an oceanic distribution, such as Homolampas, 
Paleotropus, Aspidodiadema, Paleopneustes, Colopleurus, Salenia, Pourtalesia, 
although some of these genera extend to a far less depth in the Gulf of Mexico, 
owing, however, to the special physical conditions of the Caribbean Sea and of 
the Gulf of Mexico. I will not attempt any general bathymetrical classification 
of the genera thus far obtained until after the dredgings of the coming season, 
which it is hoped will give us better material for a comparison of the deep-sea 
Caribbean Fauna with the collections of Echini brought home by the Challenger. 
As will be seen, the bathymetrical range of the new genera and species first 
collected by Mr. Pourtalés has been greatly extended, some of them reaching 
into the depths occupied by the strictly deep-sea forms mentioned above, which 
have a general distribution in the abyssal waters of the Atlantic and Pacific 
Oceans. 
