2 Mr. W. Saville Kent on Prof. E. Haeckel’s 
and it is further evident from the quotations given by Mr. 
Carter that we have here word for word a reprint of the 
original article published in the ‘ Jenaische Zeitschrift.’ This 
possession, last spring, of the volume in question enabled me 
to discuss at some length, in a communication to the meeting 
of the Linnean Society held on the 21st of June of the pre- 
sent year*, the views expounded by Prof. Haeckel concerning 
the nature and affinities of his newly created group. My 
communication here referred to, and of which the briefest 
possible notice only has so far appeared, embraces the results 
of investigations prosecuted during the last six years relative 
to that remarkable group of ‘ collar-bearing”’ flagellate Pro- 
tozoa whose existence was first discovered in America by the 
late Prof. H. James-Clark, and announced by him in the 
‘Memoirs of the Boston Society of Natural History,’ vol. i., 
for the year 18667. Four species only, representing two genera 
(Codosiga and Salpingeca), were here described by Prot. 
Clark. Later on, in the autumn of the year 1871, three out of 
these four types, with the addition of two new varieties, were 
discovered by me in the neighbourhood of London, and were 
duly announced at the meeting of the Royal Microscopical 
Society held Nov. 1 of the same yearft. With this excep- 
tion these Flagellate Protozoa, as a special and independent 
group, do not appear, knowingly, to have fallen beneath the 
observation of any other investigator. 
The importance that attaches itself to Prof. Clark’s dis- 
coveries, however, is not associated so much with his intro- 
duction to scientific notice of a new structural type, as his 
simultaneous declaration that sponges were essentially com- 
posed of sociable colonies of similar collar-bearing flagellate 
monads. This he at the time demonstrated through an 
exposition of the minute anatomy of the calcareous sponge- 
form Leucosolenia botryoides, Bowerbank, and subsequently 
in association with a siliceous American freshwater species, 
Spongilla arachnoidea, Clark§. This last important discovery 
ot Prof. Clark’s has since been fully confirmed by the observa- 
tions of Mr. Carter||, and also by myself, as shown in my com- 
munication to the Linnean Society just quoted, in which 
* « A Monograph of the Gymnozoidal Diseostomatous Flagellata, with 
a proposed new Scheme of Classification of the Protozoa, &c.” 
+ Reprinted in the ‘ Annals and Magazine of Natural History,’ 4th ser. 
vol. i. 1868. 
} Abstract published in the ‘Monthly Microscopical Journal,’ vol. vii. 
p- 261, 1871. 
§ ‘Silliman’s American Journal,’ December 1871; reprinted in the 
Ann, & Mag. Nat. Hist. for January 1872. 
Ann. & Mag. Nat. Hist. vol. x. July 1871. 
