1 92 ELEMENTAR Y A NA TO MY. [LESS. 



of the Ostrich may possibly represent the mammalian mar- 

 supial bone. 



In that man's pubis is a plainly distinct pelvic element, 

 man agrees with all of his class except those which have 

 an imperfectly developed innominate bone. 



In all Reptiles this bone appears (if the view above stated 

 as to the ilio-pectineal eminence is correct) to be fused 

 with the ischium. If this be so, then the obturator foramen 

 has no existence in Reptilia except transitorily (as in the 

 young Lizard) ; while that foramen which resembles and 

 has been described as the obturator foramen in Reptiles 

 really corresponds with the space between the brim of 

 the pelvis and a line drawn from the marsupial bone, or 

 else from the ilio-pectineal eminence, to the pubic symphysis. 

 This false obturator foramen may be called the cordiform 

 foramen. 



As has been already said, in some Insectivora and Bats 

 the pubis does not meet its fellow of the opposite side in a 

 ventral symphysis. In the Mole the pubis has so little 

 extent that the pelvic viscera pass outside and in front of 

 the pelvis. 



The pubes in Birds are very long, and bent post-axially. 

 They never meet in a ventral symphysis except in the Ostrich. 



As the ischium in Mammals is the more constant and 

 larger of the two ventral pelvic bones, it may be considered 

 rather itself to have absorbed than to have been absorbed by 

 the pubis, in those lower forms in which these two elements 

 do not seem to be differentiated. 



The ischium of man is small compared with that of 

 Mammals generally ; its proportional development is closely 

 approached, however, in the slender Loris. 



The prominent development of the spine of the ischium 

 is absolutely peculiar to man. 



The tuberosity of the ischium in the human species is very 

 small and inconspicuous compared with its condition in 

 most Mammals. Even in the very highest Apes it is much 

 larger than in man, and in the Gibbons and other monkeys 

 of the old world it is not only very large, but everted and 

 flattened with a rough surface for the attachment of a 

 thickened skin, or callosity. It is largely everted in Dogs and 

 Ungulates. In all the Edentates, except the Cape Ant-eater, 

 the ischium anchyloses with the vertebral column, and the 

 same union occurs in some Bats. 



In the Cetacea the pelvis is represented by what is pro- 



