346 WILSON. [Von. IX. 
There are two or three flagellated chambers present in this 
sponge, one of which is shown in the figure, f c., but I can 
communicate nothing as to the details of their formation, 
except that they are independent of one another and surrounded 
by a solid mass of cells. 
IV. Earty STAGES IN EGG DEVELOPMENT OF HIRCINIA 
ACUTA. 
The “Loggerhead” sponge, Hircinia acuta, is very abun- 
dant in the shallow water round Green Turtle Cay, forming 
circular masses often of very large size, which contain great 
numbers of annelids, Alpheus, and other semi-parasitic forms. 
It is with eggs in this locality during September, and probably 
for a much longer period. My observations on this form are 
very few, dealing only with the development of the ovarian 
egg and the segmentation. 
The mesoderm of Hircinia has in many regions a cartilagi- 
nous appearance, consisting of a clear non-stainable matrix 
containing cavities in which lie the cells. When the cell 
shrinks away from the wall of the cavity, the latter comes 
plainly into view, Pl. XXIII, Fig. 114 (bit of the mesoderm). 
Tracts of this sort are often found in which flagellated cham- 
bers are absent, and in such places egg cells frequently occur. 
In Fig. 114 is shown an egg cell (0. ov.) about twice the size 
of the surrounding mesoderm cells, and containing a large 
nucleus with a single nucleolus. The egg is enclosed by an 
incomplete follicle, composed of neighboring mesoderm cells 
which apply themselves closely to the wall of the egg cavity. 
During its increase in size the egg becomes stored with yolk, 
and its nucleus undergoes changes similar to those described 
for Tedanione. 
To the few mesoderm cells enclosing the young egg, others 
are gradually added, and in this way a complete follicle is 
formed, Pl. X XIII, Figs. 115, 1151, consisting of a single layer 
of cells. In Tedanione the follicular cells very early flatten out 
into a thin membrane, but in Hircinia this change does not 
take place until after the beginning of segmentation. In 
