1 
Structure of Marine Sponges. 339 
in nutriment, at all events not in the form of crude material. 
They did enclose portions of indigo, as my illustration (fig. 
zoospermia in Esperia.” .... Schmidt and Bowerbank, 
ho f 
that Trachelius trichophorus, like Euglena, progresses by 
uxley’s 
figured in the ge ' (1851, vol. vii. p. 378), so well as I 
can remember, closely resemble in form what I have just 
observed in Microciona atrosanguinea, which is a very com- 
mon sponge in this locality. — ; 
This monociliated body, which may now be seen, in great 
plurality, with every portion of the Microciona torn to pieces 
for microscopical observation, consists of a rounded triangular 
head and long cilium. The head is pyriform or shaped like a 
Florence flask with the neck drawn out to a sharp point or 
beak, and the cilium attached to the large end, close to which 
there appears to be a single granule or nucleus; but in other 
respects the head is transparent. At first these bodies are in 
