‘ ll 
' Prof. Owen on the Class Mammalia. 181 
obvious adaptive principle, in the Cetacea; but in the rest of the 
su the exception of the Elephants, they pass out of 
the abdomen, and the ee quadrupeds, as a general 
tule, have a scrotum. vulva is externally distinct from the 
anus, With the cst. again, of the Elephants, the blood 
Me into of Nash uotiee poe are two distinct discoid placenta in Callithriz as 
and Semnopithecus ; whilst in Mycetes, as in Troglodytes, 
ras eee oh plat enta. 
The structure of oe disepad placenta in the Pteropus, like that of the Rat, mor 
resembles that of the feetal portion of the we Saas in the Bit than that of the 
and t 
ellulo-vascular s lacenta of the Quadrumana ; his difference, with the 
Gale st ae. oF fhe larger eae “ans pen to ‘i to greatly outweigh 
the of resemblance in mere ard form of the placenta. Any argument 
1n favor of oy affinity of pd Cheiroper to the Quadrumana, "toed on that ia 
- Tesemblance, must be a: ted by the prevalence of the double discoid placenta 
ips Quadr ana, Since | Hu nter first made known that m 
persed Which, from a comparison of og foetus now preserved in the Museum 
( > en Royal College of Surgeons, I believe to be the ‘ Wrinkled Baboon’ of Shaw 
feacus rhesus, Desm, , Professor Breschet ses described and figured the two sep- 
irate discoid Placente in the small South American S uirrel-monkey (c oagaete 
in i sabe sm.), and in the 
of 
54 
3 One general term as as applica cable es the whole. 
te ; cond argument for the association of the Znsectivora, ne era and Roden- 
‘ = the Quadrumana i is taken from ailag ed pera ‘of cereb aap stru wag ; 
erveau d'un R. 4 celui d'un Insectivore ; il existe aussi 
Une resem paneer différe 4 peine de ! » ccllie de am 
es 
elance piimten t the brai . : Io m 
F in Rodentia and certain poirot n my paper 
a y, Ne Bra rains of the Marsupialin (Phii. Trans., antl I have described and figured 
aie; ‘ease the us te of a Beaver (see fig. 2, p. 178) and that of a small Monkey 
bi 180). showing? the laa of cerebral con volu — in 
no 
tia and 1 z nse fndetbore sper it is mitended by pte more important t difference 
nimal mal Econom Sci Nat., tom. cit., p. 96, 
, 4to, 1780. ae des rogers oy 
{ Bidrage tot de Kenn ennis van den P at an Bosman, 4to, 1851, V.der Hoe 
Ptes Rendus de l’Acad. des oko, » daciter 19, 1869, 
