244 Analytical Notices of Books. 
it projects inwards the inner lining of the ovary, which becomes gradually 
thinner, until at length it bursts, and the ovum is released from its con- 
finement by a slow and gradual process of expulsion into the cavity of the 
ovary. Thence it is propelled by degrees into the oviduct, where it is 
surrounded by a layer of albuminous matter, inclosed within a double 
coat. 
Passing in silence over the impregnation and expulsion of the ova, and 
their attachment to the undeveloped legs beneath the tail of the mother, 
the authour, in the seccnd section, resumes his observations at the period 
immediately succeeding the latter process, and proceeds at once to describe 
the new laid egg, which consists of the six following parts. 1. The 
V%tellus; which occupies by far the largest portion, is of a brown colour, 
and consists of an aggregate of minute granules varying in diameter from 
torts to;735% ofa line. These granules seem to adhere together by their 
own power of cohesion, without the intervention of any fluid, and are of 
a highly viscid consistence, which may be rendered much firmer for 
examination by maceration in spirit of wine or diluted nitric acid, the 
former giving them the fixity of cheese, the latter exhibiting them in the 
shape of rays passing from the centre to the circumference. 2, The 
Embryo; which shortly after the attachment of the eggs beneath the tail 
of the mother, loses its original form, and spreads itself over the entire 
surface of the vitellus, in the shape of an exceedingly thin layer, irregu- 
larly reticulated, and of a marbled appearance. The authour has not 
been able to observe the passage from its former to its present state, but he 
thinks himself justified in assuming the identity of the two parts, which 
is confirmed by Herold’s researches on the eggs of spiders, where a similar 
change takes place immediately after their expulsion. 3. The Membrane 
of the Vitellus ; which incloses the two former parts, is highly transparent, 
perfectly smooth on both surfaces, and extremely thin, and is not lost, as 
in the chicken, during the developement of the embryo, but remains to be 
thrown off with the other membranes, when the latter quits its shell. 
4. The coriaceous coat ; which surrounds the last, is, like it, very transpa- 
rent, but much thicker, highly elastic, and of an almost coriaceous 
texture ; it is perfectly smooth on the whole of its inner surface, but only 
on one small portion of the outer. 5. Between the two last named coats, in 
the new-laid egg, there exists a cavity of some little extent, occupied by a 
