All are a(|uatic, and with few exceptions marine. 
He describes seven genera of Sponges, all of which are, with 
one exception, marine ; and all, with one exception, contain either 
calcareous or silicious spicula. 
The literature of the Sponges after this consisted to a gi'eat 
extent of desultory papers, appearing from time to time in various 
Scientific Journals, but, no attempt was made to continue the work 
begun by Johnson, until the Hay Society published Dr. Bower- 
bank’s valuable monograph on the Briti.sh Spongiadje ; in this 
monograph the Author has to .some extent ignored form as a 
genera, or even specific character, and has adopted the microscopic 
structure as shown in the form and armngement of the spicula. 
Ihe position of the sponges .seems to be midway between the 
amoeba) and the foraminifera, tfio former consisting entirelv of 
sarcode, and without any kind of spicula or external shell ; and 
the latter possessing a shell composed of one or more charaber.s ; 
the sponges although destitute of an external .shell posse.ss a 
keratoso skeleton, strengthened in the majority of cases by calca- 
reous or sdicious spicula. 
TIio vital and therefore the most important part of the sponge 
is the sarcode, and with your permission T shall endeavour to give 
as lucid a description as possible of the important part performed 
by this material, and perhaps the best idea of it can be obtained 
by soaking a piece of isinglass in water, the living sarcode, like 
the .softened gelatine, is semi-pellucid, varying in colour from 
external causes, and during life insoluble in water. 
The absence of special organs in the Amceba) Sponges, &c., 
clearly indicates that the power of assimilating nutriment is pos- 
sessed by this material, and identifies it with the sarcodous system, 
covering the digestive surfaces of animals ; we can trace the pre- 
sence of this wondrous matter from the highly developed mammal 
to the humble ainceba, other organs may become obsolete, and at 
last we find that sarcode alone remains. And this apparently 
inert, shapele.s.s, structureless mass of jelly is endowed with the 
power of producing those elegant forms known as polycystina and 
foraminiferji, or as in the case with the sponges, the multitudinous 
varieties of spicuLi, (Bowerbank figures and describes between two 
and three hundred distinct forms of spicula, and does not then 
describe all the forms,) and even build up with silex ab.stracted 
