SILICIOUS AND HORNY SPONGES COLLECTED BY THE 

 U. S. FISHERIES STEAMER "ALBATROSS" DURING 

 THE PHILIPPINE EXPEDITION, 1907-1910 



By H. V. Wilson 

 Kenan Professor of Zoology in the University of North Carolina 



INTRODUCTION 



The collection of Philippine sponges included onlj a few Calcarea. 

 These are reserved for separate study. The Hexactinellids were 

 placed in the hands of the late Professor I. Ijima, of the University 

 of Tokio. 



The following report, it is hoped, will prove useful to zoologists 

 entering upon the work of classification, as something of a guide to 

 the contemporary taxonomy of sponges, more especially of the 

 tetraxonid sponges, and to the literature dealing with this subject. 

 It may be taken, at the date of writing, as an index to the families 

 and genera of the Astrophora, Hadromerina, Sigmatophora, to the 

 subfamilies of the Halichondrina, and to the families and genera of 

 the Lithistida. In places I have gone more into detail, attempting 

 for instance to list the species of Sigmatophora and Lithistida that 

 have been established since 1903 (the date of the Tierreich synopsis, 

 Lendenfeld, 1903). Doubtless there are omissions. 



The phenomena that are roughly grouped under the head of varia- 

 tion force themselves upon the attention of all who undertake to 

 classify sponges. As in former papers (especially 1901) I record, 

 throughout the body of the report, considerable data that come 

 under this head. Such data I am aware can not in themselves lead 

 to any definite conclusions concerning the causes of change — namely, 

 conditions under which changes appear. But they do add to our 

 knowledge of the kinds of variations that occur. They contribute 

 to what we may call the classification of variation phenomena, with- 

 out a knowledge of which experimental work on the production of 

 new races and the improvement or even the safeguarding of old ones 

 can scarcely go far. 



Variation phenomena in a group of such plastic organisms as 

 sponges become involved, perhaps more directly than in many other 

 groups, in the practical work of classification — that is, the seating 

 up of categories or the assigning of bodies to categories already in 

 use. As I point out under Donatia and Tetilla, it is only by arbi- 

 trarily disregarding variation that we can rigidly adhere to a mode 



8170&— 25 2 273 



