1885.] Embryology. 903 
Reptiles and Batrachians—G. A. Boulenger gives a list of 
thirty-one reptiles and sixteen batrachians from the province of 
Rio Grande do Sul, Brazil, collected by Dr. H. von Ihering. The 
new species are Enyalius theringii, and Liolemus occipitalis 
(Lacertilia), and Coronetta theringit. 
EMBRYOLOGY. 
ON THE AVAILABILITY OF EMBRYOLOGICAL CHARACTERS IN THE 
F o 
est major subdivision of the Endocyemate subphylum em- 
braces forms in which the ovum is invested by a zona radiata, 
external to which comes an additional investment of albuminous 
matter secreted by the oviduct, this albuminous envelope being 
usually in turn covered by a fibrous membrane immediately over- 
laid by a porous, more or less calcareous shell, also secreted by 
the oviduct. Chalazæ are often developed. The cleavage is par- 
tial, the germinal matter, as a rule, forms but an insignificant part 
of the whole ovum, and is aggregated at one pole of the latter as 
a blastodisk. The blastodermic vesicle is developed from the 
blastodisk by epiboly upon the vitelline mass, which is finally in- - 
cluded so as to occupy a ventral position in the vesicle. Devel- 
opment is at most viviparous only during the very earliest stages 
or while the ovum is passing through the oviducts, or more or 
less entirely oviparous, or quite ovoviparous. The allantois is 
greatly developed, but never associated in the development of a 
true placenta, though it is usually respiratory in function. 
Under this definition the three following groups seem to be 
appropriately included: 
a. Ova buried in the earth or sand by the parent, and left to be 
incubated by the heat of the sun. Some species ovovivipa- 
rous. Reptilia. : 
ő. Ova incubated by the parent in a nest specially constructed 
for the purpose. Aves. 
c. Ova incubated by parent in an abdominal marsupium or in 
a nest at the end of a burrow. Recently hatched young nour- 
ished by the parent for a time upon milk secreted by mammary 
glands. No functional uterus. Ornithodelphia. 
It may also be noted that with group å the distinctly warm- 
blooded series of the Chordata begins. The relatively high tem- 
P _rature of the body of the adult plays an important part in incu- 
“tion or in accelerating metabolism in the embryo. .The pre- 
c*ding three groups, on account of the many features of resem- 
“ance and reptilian traits possessed in common (group c being 
! Edited by JoHN A Ryper, Smithsonian Institution, Washington, D. C. 
