1886. ] POSITION AND CLASSIFICATION OF SPONGES. 559 
Whilst the anatomical and embryological work of recent authors, 
particularly of F. E. Schulze and his pupils, has made us acquainted 
with the structure of Sponges in a satisfactory manner, our know- 
ledge of species, which was formerly practically confined to those 
from the Mediterranean and the Atlantic, has been greatly extended 
by the collections made during the voyages of the ‘Alert’ and 
‘Challenger’ in all parts of the world, and by my own labours in 
the Australian seas. 
I think, therefore, that the time has now arrived to endeavour to 
establish a classification of Sponges, and to discuss the position 
which the Sponges, as a group, occupy in the scale of Nature. 
In an Appendix to this paper a nearly complete list of publications 
on Sponges is given. It has been made by interpolating old, new, 
and omitted papers in D’Arcy Thomson’s (1495) list of 551 papers, 
the references in which have been verified. I must express my 
thanks to Mrs. v. Lendenfeld and to Mr. A. Dendy for their share in 
this work, and also to Mr. Ridley for his kindness in allowing us 
to use his most valuable MS. notes on this subject. 
In the section on the systematic position of Sponges, the principal 
views held on the subject are discussed, and reasons are given for 
considering the Sponges as the first Phylum of the Grade Ccelentera, 
which arrangement has been adopted in this paper. 
The main classification of the Orders is the result of my own anato- 
mical work, and has been arrived at independently of other authors. 
It affords me much pleasure to state that this classification is, in the 
main, similar to that established by Vosmaer (1550), although we 
have arrived at our results in different ways, and our diagnoses 
differ accordingly. 
To that section of this paper which deals with the arrangement of 
the Families and Subfamilies, and the enumeration of the principal 
Genera, Mr. A. Dendy has contributed the portions relating to the 
Suborders Clavulina and Halichondrina with the exception of the 
Tethyde and Chalininee. The portions relating tothe Hexactinellida 
and Tetractinellida are compiled from the recent papers of Schulze 
(1369), Sollas (1458), Vosmaer (1550), and Zittel (1639). The 
remainder is based on my own MS. notes. 
II. NoMENCLATURE OF THE SPICULES. 
Various terms for the spicules found in Sponges have been used 
by different authors. In consequence of this a certain confusion 
has arisen with regard to the meaning of the terms employed. 
Vosmaer (1550) made a chivalrous attempt to establish a satisfactory 
Nomenclature, which, however, has unfortunately not been accepted 
by recent authors on Sponges except myself, so that it only added 
to the already existing confusion, 
Recently Sollas, Ridley, and Dendy have established a new nomen- 
clature for Monaxonid spicules, which I have agreed to adopt, and 
which has been used by them and myself. I do not think it perfect, 
but I am certainly not in a position to replace it by anything better, 
and therefore adopt and explain it in this paper. Schulze’s nomen- 
