348 
ARTHUR DENDY. 
The contents issue through the liilum under the form of a 
gelatinous mass, in which the ovibearing cells and their 
contents appear to be embedded entire The 
ovibearing cells are developed into spherical ampullaceous sacs, 
communicating with the afferent canals The ovi- 
bearing cells do not burst and allow their contents to become 
indiscriminately scattered through the gelatinous mass in 
which they are embedded, but each becomes developed 
separately and entire in the following way, viz. the ovules and 
granules of the ovibearing cell subside into a granular mass 
by the former losing their defined shape and passing into small 
monociliated and uniciliated sponge-cells ; this mass then 
becomes spread over the interior surface of the ovibearing cell, 
leaving a cavity in the centre into which the cilia of the mono- 
ciliated sponge-cells dip and keep up an undulating motion ; 
meanwhile an aperture becomes developed in one part of the 
cell which communicates with the adjoining afferent canal, 
and thus the ovibearing cell passes into an ampullaceous 
spherical sac.” 
It is astonishing how such a precise account, coming from 
the pen of so careful an observer as Mr. Carter, has received so 
small a share of attention from subsequent writers. I do not 
see any reason to doubt the accuracy of Mr. Carter’s statements, 
and I shall presently endeavour to show that the flagellated 
chambers develope in precisely the same manner in the em- 
bryos of Stelospongus. 
Two other authors, viz. Metschnikoff and Goette, have 
described a mode of development of the flagellated chambers 
which appears to me to agree pretty closely with that observed 
by Mr. Carter in the gemmules of Spongilla, and by myself 
in the embryos of Stelospongus. Unfortunately, I am 
unable to obtain access to the original papers of either of these 
authors, and I am obliged therefore to content myself w T ith the 
very brief abstracts, fortunately accompanied in the first case 
by figures, given by Vosmaer (18). 
Metschnikoff (12) describes and figures the embryo of 
Halisarca duj ardini at a certain stage as consisting of an 
