M A US U PI AT A. 
7 
they are found in both sexes of the marsupial animals; are 
relatively longest, struightcst, and most slender in the Pera- 
meles; tluttest, broadest, and most curved in the Koala,— 
sometimes, as in the Wombat, they are articulated to the 
pubis by two points. Around these bones the cremaster 
muscle winds, and they serve important purposes in relation 
to the' generative economy of the Marsupiata. 14 In die 
female they assist in producing a compression of the mammary 
gland necessary u> the alimentation of a peculiarly feeble 
offspring, and they defend the abdominal viscera from die 
pressure of the young, as these increase in size during their 
mammary or marsupial existence; and still more when they 
afterwards return to the pouch for temporary shelter 1 /’ 
One of the most interesting features in the skull of the 
Marsupiata consists in die permanent separation of the 
bones; diese do not anchylose in the adult and old animals 
as do many of the bones (especially those of the cranial por 
don of the skull) in the placental series: the temporal bone 
generally preseuts a permanent separation of the squamous, 
petrous, and ty mpanic elements. “ I have observed,” says 
Professor Owen, “ this reptile like condition of the bone in 
the mature skulls of an Ursine Dasyure, a Virginian Opossum, 
a Perameles, in different species of Potoroo (or Kangaroo- 
rats) and Kangaroo, in the Wombat and in the Koala/’ 
The palatine pordon of the skull is generally very imperfect, 
presenting large openings. In all the species of the group, 
with the cxcepdon of the Echidna, Omithorhynehus, and 
Toraipes, the angle of the jaw is bent inwards, so that in 
viewing the underside of the jaw each ramus presents a 
more or less flattened and pointed process encroaching upon 
the interspace of the two branches behind, whilst in the 
1 Sec Professor Owen’s paper on the Osteology of the Marsupialia , in the 
Proceedings of the Zoological Society for 1838. 
