152 OPHIURANS. 
occurs in the West Indian region where Holothuria captiva, from which it can 
scarcely be distinguished except by the anal teeth, is common. It occurs in 
the mienasts region with Holothuria dificilis from which again the anal teeth 
are its one distinguishing character. On the other hand, it is utterly unlike 
any other Actinopyga save for the presence of the anal teeth. Pearsons is 
divest certainly right in removing it from Actinopyga but he throws no light 
on the problem of its relation to the species of Holothuria mentioned. Pos- 
sibly the presence of anal teeth is, in this case, not even a valid specific character 
but it is hard to believe this is the case. At any rate, the occurrence of this 
perplexing form, originally described from Florida, on the shores of Easter 
Island is a matter of unusual interest. 
Summary of the Echinoderms collected by the Agassiz-Albatross Tropical Pacific 
Expeditions of 1891, 1899-1900 and 1904-1905. 
As the present report is the last of those dealing with the Echinoderms 
collected by Mr. Agassiz on his Tropical Pacific Expeditions, it is fitting that 
the chief additions to our knowledge of the taxonomy of the Echinodermata 
should be summarized. 
The Crrvorps proved to be the least abundant of the five classes and only 
nine species were taken. Of these two were unidentifiable but six of the 
others were new. There is no record of the number of specimens. The most 
notable of the crinoids are the two stalked forms Bathycrinus equatorialis A. H. 
Clark and Calamocrinus diomedae A. Agassiz. The latter, one of the most 
notable stalked crinoids as yet taken, was made the subject of a detailed mono- 
graph (Agassiz, 1892, Mem. M. C. Z. 17, no. 2). 
The AstERorps were fairly numerous but there were few species of ex- 
traordinary interest. In all more than 1,300 specimens were brought home, 
representing ninety species, of which sixty-nine were new. Of new genera, 
five were established. The most notable forms are probably the two species 
of the new genus Albatrossia, the numerous species of Hymenaster, and Zoro- 
aster, and the Brisingidae. 
The OpHIURANS were numerous both in specimens and species but unfor- 
tunately there is no complete record of the number of specimens. There were 
at least ninety-seven species taken, and of these sixty were new. One new 
genus was described based on this material. The most noteworthy brittle-stars 
are Gymnophiura mollis, Sigsbeia lineata, and Ophioderma pentacantha. 
