VI INTRODUCTION. 
It will be noticed that the treatment of the difterent families varies slightly, some being 
considered in greater detail than others. It has not seemed necessary to treat the relatively 
well known groups with that minuteness which is called for in the case of the more obscure 
and difficult families. 
In the lists of the species by stations the stalked species described bij Professor DOderlein 
are included. The species of the family Bourgueticrinidae {minimus, nodipes, poculum and iveberi) 
are assigned to genera in accordance with my recent revision of that family, in "Die Crinoiden 
der Antarktis" (Berlin, 19 15), and the new species of Isocrimis {Sibogac) is assigned to the 
genus Endoxocrijius, Isocrimis as now understood, both b)- Professor Doderleix and myself, 
being exclusively West Indian. 
The references to the literature include all in which original matter occurs, but those 
in which no original matter is found are omitted. 
THE "SIBOGA" COLLECTIOxN. 
Of all the collections made by exploring expeditions since the time of the "Challenger" 
that of the "Siboga" excels in the number of species and of individuals, and in the number 
and diversity of those small forms too often discarded as the "young" of the larger types. 
In making this statement I am assuming that comparison with the collections of the 
"Albatross" would not be quite fair, as that ship took her first dredge haul on March 22, 
1883 and has been almost continuously at work ever since, that is to say for a period of 
nearly thirty-four years, cruising throughout the western Atlantic and Caribbean regions, and 
over the greater part of the Pacific, and spending the time from November 7, 1907 to January 
29, 1 9 10 among the Philippine Islands and in adjacent waters, where she covered a part of 
the territory previously worked by the "Siboga". 
The route traversed by the "Siboga" carried her over what is possibly the most inter- 
esting region, zoogeographically speaking, in the whole world; she gathered the Australian 
fauna at the Aru Islands, and the Malayan fauna in the Sulu archipelago, and paid particular 
attention to the intermediate region, among the Moluccas and about the Lesser Sunda Islands 
which, in water of moderate depth, possess a fauna certainly distinct from that of the Philippines 
and adjacent islands as we know it, and related rather to that of southern Japan, though from 
certain indications it may possibly be a continuation of the deeper Australian fauna which 
extends itself further to the northward and westward than does the fauna of the littoral. 
There are known from the recent seas 576 species of crinoids, representing 142 genera 
distributed among 28 families and subfamilies. Of these, 76 species, included in 22 genera and 
6 families, are stalked, while 500 species, 120 genera and 22 families and subfamilies are of 
the unstalked comatulid type. 
In the course of her explorations the "Siboga" collected 163 species (149 comatulids 
and 14 stalked forms), of which no less than 73 (64 comatulids and 9 stalked species) were 
new to science, representing an increase of 14.5 percent in the number of known forms. 
These 163 species fall into 71 genera (65 comatulid and 6 stalked), just over half of 
