96 SIDNEY F. HARMER. 
ment of the ovicell is dependent on the activity of the poly- 
pides. On decalcifying a number of colonies of Lichenopora, 
a considerable number of all ages and sizes will be found to 
be practically empty. In studying the embryonic development, 
time is simply wasted if preparations are made of colonies in 
which the polypides are not for the most part fully active and 
functional, or at least in which the polypides have not recently 
been functional. A recently degenerated polypide may be 
difficult to distinguish, in a preparation of an entire colony, 
from a functional polypide; whereas it is quite easy to recog- 
nise the small, compact, brown body which indicates that 
the histolysis of the polypide took place at some more distant 
period. 
The conditions under which the embryos are nourished 
appear to be very different in different Cyclostomes. In 
Crisia ramosa I have shown that the embryos are contained 
in a highly protoplasmic reticulum, which, it can hardly be 
doubted, serves for the transference of nutriment to the de- 
veloping larve. In C. eburnea the reticulum is reduced to 
a minimum, and the path of the nutrient substances is pro- 
bably somewhat different from that inC. ramosa. Analogous 
phenomena probably occur in the genus Lichenopora; and 
L. verrucaria may be compared with C. ebur nea, in which 
the reticulum is but slightly developed. Although I have not 
yet been able to obtain a supply of material for the proper 
examination of other species of Lichenopora, I have obtained 
a series of sections through a single fertile colony of L. hispida, 
Flem. The ovicell contains a comparatively small number 
of young secondary embryos, which are embedded in a large 
solid nucleated mass which probably corresponds, in func- 
tion at least, with the “ follicle” of C. ramosa (cf. 6, Pl. 
xxii, fig. 6). 
My examination of this single series of sections of L. 
hispida enables me to state that the embryonic development 
of that species probably differs to a very considerable extent 
from that of L. verrucaria. Another curious difference 
between the two species may here be pointed out. While in 
