7& 



PHYLUM CHORDATA : CLASS MAMMALIA 



few cases temporarily) into a single or paired scrotal sac, 

 lying, except in Marsupials, behind the penis. 



The ovaries are small. Except in Monotremes, the genital 

 ducts of the female are differentiated into — (a) Fallopian tubes ^ 



PA 



I. PA 



• Fig. 467. — Posterior view of the occipital region of the skull of a 



young cat. 



PA., Parietal; I. PA., inter-parietal; SQ., squamosal; S.O., supra-occipital; Z., 

 posterior end of the zygomatic process of the squamosal ; PER., outcrop of the 

 periotic bone (mastoid portion) ; EX.0., ex-occipital ; TY., tympanic bulla ; 

 CO., occipital condyle, formed by the ex-occipital ; F.M., the foramen magnum, 

 through which the spinal cord passes out from the brain. 



which catch the ova as they burst from the ovaries ; (b) a 

 uterine portion in which the young develop ; and (c) a vaginal 

 portion ending in the urinogenital aperture. In Monotremes 

 the two ducts are sim,ple, and open separately into the cloaca ; 

 in Marsupials there are two uteri and two vaginae ; in 



