NARRATIVE OF THE CRUISE. 
043 
mentioned in the family of Teichonidse two genera, one created by Carter, the other 
new. The whole collection being represented by thirty species (twenty-three new) ; 
four species (one new) have been found to belong to the Asconidae, ten species (seven 
new) to the Syconidse, fifteen species (fourteen new) to the Leuconidse, and one species 
(new) to the Teichonidse. 
“ The Challenger collection of Horny Sponges proved to be but little larger than that 
of Calcarea, consisting of thirty-seven species, twenty-one of which have been found to 
be new. The collection proved, however, to embrace all the genera of the group distin- 
guished up to this time, with the exception of Darwinella, Aplysilla , Aplysina, and 
Phyllospongia. The author has abstained from describing three species represented only 
by specimens quite devoid of soft parts, the whole systematic proceeding of the Memoir 
having been conducted according to the principles upheld by Professor F. E. Schulze, 
and demanding the examination of the soft parts in no less degree than of the properties 
of the skeleton. It is for the first time that a comparatively large collection, of Keratosa 
has been classified and described according to the present state of our spongiological 
knowledge. But in spite of the fact that the brilliant researches of F. E. Schulze 
have considerably increased within the Keratosa the number of characters fit for 
systematic application, the author- of the report is still of opinion that on the whole the 
arrangement of the group lately proposed by Dr. Yosmaer, and based on the investiga- 
tions of F. E. Schulze above mentioned, is still to be regarded as a provisional one, and 
that so long as Spongiology will not attach due influence to Comparative Physiology in 
its systematic proceedings, no hopes can be entertained of a natural arrangement of the 
Keratose Sponges. This is the chief idea of the Memoir, and even the description of the 
Challenger specimens is to a certain degree subordinated to it and devoted to its founda- 
tion. The Memoir opens with the discussion on the organisation of the Keratosa in 
general and on their chief systematic characters. Its results are that all these characters 
(namely the structure of the horny skeleton, the tendency of the skeletal fibres to take in 
foreign bodies, the presence of filaments, the differences iir anatomical organisation) are 
either of little systematic importance, or of such a relative nature that the subdivision 
of the Keratosa into two main groups (orders) as proposed by Hyatt, Carter, and 
v. Lendenfeld is impossible. On the other hand the author comes to the conclusion that 
a direct subdivision into families as suggested by Yosmaer is also of an undoubtedly 
artificial nature ; for such a subdivision, although it pays attention to the relative 
character of the main , systematic characters of the Keratose Sponges,- does not give 
sufficient weight to the circumstance that the application of these characters — namely 
the structure of the canal system, and the properties of the skeletal fibres, whether 
homogeneous or heterogeneous — gives rise to systems which are antagonistic to one 
another ; and furthermore, the representatives of Dr. Yosmaer’s families show such many- 
