( 904. ) 
XI. Some Remarks on the Physiology of the Egg, communicated 
ina Letter from John Ayrton Paris, M.B. to William George 
 Maton, M.D. V.P.L.S. $c. $c. 
Read April 4th, 1809. 
Dear SIR, 
Tue extensive range which the Ovipari form in the scale of ani- 
mated existence renders the physiology of the egg a subject of 
extraordinary interest. and importance to the disciple of Lin- 
neus: I am therefore induced to hope that the communication 
of any new facts relative to its organization and development 
will be received by you as an acceptable tribute to the cause 
of natural history. 
The ova, or germs of oviparous animals admit of an evident 
division into two orders. I. The PEnrzEcr, and II. the IMPER- 
rect. The former are deposited by the Aves, Serpentes, and 
by most Oviparous Quadrupeds, and are completely formed in 
utero; whilst the latter, produced by some of the Testacea, Am- 
phibia, and by most Pisces, acquire additions after their ex- 
. clusion. The observations contained in this memoir relate more 
particularly to the class Aves, the history of whose ova com pre- 
hends whatever is interesting or important in the germs of in- 
ferior animals. The egg, when completed and deposited, con- 
sists of the following parts :—* 
1. Vitellus or yolk, with its capsule and cicatricula; 2. The two 
Albumina 
