133 
Bibliographical Notices. 
vering experimentalist was mentioned by those who write for the 
public ; and foreigners were compelled, almost reluctantly, to ac- 
knowledge that the Scotch savans had been for years familiar with 
facts and pheenomena, for the discovery of which, in a less perfect 
manner, they were seeking the praise and honour of their competi- 
tors. The present publication will not only prove Sir John’s inde- 
pendent discoveries and priority, but it will place its author in the 
first rank of those who gain deserved honour by their talent for ori- 
ginal observation, and by that devoted love to a subject which car- 
ries one unwearied through years of patient experiment, heedless of 
any future reputation, and regardless of being forestalled by the fear 
of anticipation which urges on too often to hasty publicity. 
In our present notice we shall confine ourselves to the Hydroid 
Zoophytes. And were we to distinguish these according to diver- 
sity in their embryology, the researches of Sir J. G. Dalyell would 
enable us to divide them into three families, viz. (1.) those which 
“ propagate the young in their own likeness by gemmation or bud- 
ding from the side (2.) those which in the foetal or larva state re- 
semble t\iQ Medusis and (3.) those which produce an unciliated 
roundish corpusculum, that, on its escape from the ovarian vesicle, 
assumes the shape and motions of the Blanaria. 
The first family is limited to the freshwater Hydrse, and need not 
now detain us, excepting only to remark that our author appears 
never to have observed these polypes to propagate by any other 
means than by gemmation. Their wdnter eggs, described by others, 
do not seem ever to have come under his notice. 
The species of the second family ascertained to be so by our 
author are Tuhularia indivisa, T. larynx, T. ramosa and Laomedea di~ 
chotoma. The similarity of their larvae to miniature Medusae in form, 
in structure and in habits is so very remarkable, that, even after 
having witnessed their progressive development and birth from the 
parent. Sir John can scarcely bring himself to admit their relation- 
ship. But there can be no doubt of this, and the metamorphosis is 
one of the most wonderful in the animal kingdom. We know not 
that we could make more distinct to our readers the idea of these 
larvae than by the comparison of them to Medusae which has just 
been made, and must therefore refer to the volume itself for the full 
details. The interest of the zoologist will not flag in their perusal, 
and in the examination of the figures ; although there is certainly 
wanting that precise and regular specification of embryotic changes 
which distinguishes the memoirs of Van Beneden. 
The third family embraces Tuhularia ramea, Thoa halecina and 
Beanii, Sertularia polyzonias, ahietino, rosacea, pumila, argentea and 
arcta, Antennularia antennina and ramosa, Plumularia falcata and 
pinnata, and Campanularia verticillata. All these produce a roundish 
oviform body, which on, or even previous to, its eduction from the 
ovarian receptacle assumes the figure of the worms of the genus 
rianaria. Hence it is called a pla?tule by our author. It appears to 
be an immediate evolution from the central pulp, the colour of which 
it has on its birth ; but some species produce planules of at least two 
