226 LIVERPOOL BIOLOGICAL SOCIETY. 
nuclei are small and not very conspicuous, apparently on 
account of the opaque protoplasm of the cells. The nature 
of these cells seems to be distinctly different from that of 
the much smaller spindle-shaped cells described in Aa- 
nella mammillata, n. sp. (page 211). In the latter species 
the granules of the cells are distinctly spherical, clear, and 
highly light-refracting. In Sezrzola the granules are opaque, 
and apparently of no definite outline. Further, in Aaznella 
the spindle-cells run in strands along the chief masses of 
spicules, and suggest at once that they might be ‘‘ sclero- 
blasts.” But in Seriola such a relation between the 
spindle-cells and the spicules does not seem to exist. 
On the contrary, quite independently of the presence or 
absence of spicules, the strands of those cells permeate 
the choanosome in an irregular fashion, giving off numer- 
ous branches (Pl. XIII., fig. 8). Further, 1 have not 
been able to find any connection between those strands 
and the incurrent and excurrent canals, or with any other 
structure. ‘Transverse sections through the strands are 
frequently met with in preparations, and they show a 
‘“myocytes’’ seem to be similar 
structures, but they differ from those cells in Seriola 
round outline. Sollas’s 
by chiefly occurring “‘ concentrically arranged about the 
openings of the water-canals.”’ Still I shall not be sur- 
prised if future investigations prove those cells to be neuro- 
muscular elements. 
In regard to the systematic position of Sezriola compacta 
Professor Sollas wrote me as follows :—‘‘ The choano- 
somal spicule is a characteristic oxyaster, the ectosomal 
microsclere is a typical sanidaster; this latter places the 
sponge in the Sanidasterima. Of the genera of this group 
it approaches most nearly Stryphnus, but differs from all 
the species of this genus which I have seen. The sani- 
daster is a better sanidaster, 1.e., more typical and regular 
