the Embryo of Purpura lapillus. 
21 
phenomenon, is one stage in the normal process of develop- 
ment. 
Notwithstanding my own conviction of the truth of my 
conclusions, — based upon the careful and repeated observation 
of certain most important phenomena in the history, which 
have been altogether overlooked or very imperfectly seen by 
my predecessors, whose ignorance of these facts has vitiated 
the whole of their interpretation of the process, — I might have 
hesitated in thus giving a somewhat confident expression to 
them, since the limitation of my time prevented me from 
working-out the investigation with the completeness I should 
have desired. But during my prosecution of the inquiry, I 
had the advantage of being able to satisfy my friends, Mr. G. 
Busk and Mr, T. H. Huxley, of all those facts on which my 
conclusions are based; and the former of these distinguished 
naturalists and excellent observers, having remained at Tenby 
for some time longer than myself, not only verified these by 
his own independent observations, but also supplied some ad- 
ditional facts of great value in regard to the earlier stages of 
the process, which he has kindly allowed me to incorporate in 
the history which I shall now offer. I cannot but believe, 
therefore, that the joint testimony of my friends and myself, 
as to what we have ourselves repeatedly witnessed, should re- 
move all reasonable doubt about the facts of the case ; and the 
inferences from these facts seem inevitable. 
Each of the flask-shaped ovigerous capsules of the Purpura 
lapillus contains a large number of egg-like bodies (usually 
from 500 to 600), in the midst of a pellucid viscous liquid, 
very like ordinary white-of- egg. (Plate III., fig. 1). These 
do not at first present any feature of dissimilarity, one from 
another. They are all spherical, or nearly so, in form ; and 
their diameter is pretty uniformly '0075 of an inch. Not- 
withstanding the statement of MM. Koren and Danielssen, 
that they have " a delicate chorion and a vitelline membrane," 
I have not been able to detect any appearance distinctly indi- 
cating the presence of a membranous investment around them. 
When crushed, they are found to be composed of vitelline 
matter, consisting of ovoidal particles strongly resembling 
starch-granules (fig. 2.) in size, form, and general appearance, 
but of albuminous composition, imbedded in a fluid loaded 
with minute granular particles, many of which seem to be 
oleaginous, i have not detected in any of them, either a 
germinal vesicle, or any body which could be considered as 
representing it ; but I have occasionally met with what ap- 
peared to be the void space, which the germinal vesicle might 
have formerly occupied. Having, for the sake of comparison, 
