358 THE ANATOMY OF VERTEBRATED ANIMALS. 



immediately bounds the Sylvian fissure, one which runs along 

 the upper margin of the hemisphere, and one between these 

 two. The corpus callosum is long, and the anterior commis- 

 sure well developed. 



There is a museulus choanoides in addition to the usual 

 ocular muscles, and the rudimentary nictitating membrane is 

 said to possess a muscle. 



The tensor tympani arises from a deep pit above the prom- 

 ontory, and its tendon passes directly outward to the mal- 

 leus. 



The male is devoid of Cowper's glands. The penis has a 

 bone, and the glands becomes swollen during copulation, so as 

 to prevent the withdrawal of the penis from the vagina of the 

 female. The ovary of the female is enclosed in a sac of the 

 peritoneum, and the uterus has long cornua. The umbilical 

 sac is drawn out to a point at each end. 



The Dogs (including the Wolves, Jackals, and Foxes, under 

 this head) form the most central group of the Carnivora, which 

 may be termed the Cynoidea* From these the Bears, 

 Weasels, and Procyonidm depart, on the one hand, and the 

 Cats, Civets, and Hyeenas on the other. The former grou)) 

 [Arctoidea) have the cavity of the bulla tympani undivided 

 by a septum. The paroccipital process is not applied to the 

 posterior wall of the bulla. The mastoid process is widely 

 separated from the paroccipital. The condyloid foramen is 

 not merged in a common opening with the foramen lacerurn 

 jyosticuni. The intestinal canal is devoid of a cseouva. The 

 large penis has a bone which is not grooved ; there are nc 

 Cowper's glands, and the prostate is small. 



In the latter group (Ailuroidea) the bulla tympani is large 

 and rounded, and the septum, which is rudimentary in the 

 Cynoidea, is so much enlarged as to leave only a narrow 

 aperture of communication between the two chambers. The 

 par-occipital is closely applied to the posterior wall of the bulla. 

 The mastoid process is often obsolete. The condyloid foramen 

 opens into a fossa common to it and the foramen lacerum 

 posticum. All have a short cascum. The penis is small, ar.d 

 lits bone small, irregular, or absent. They have Cowper's 

 'glands and a well-developed prostate. 



The Gynoidea are all digitigrade, and resemble the Dog 

 in their dentition. The Arctoidea are plantigrade, while the 



* See Prof. Flower's important memoir on tlie Glassifleation of the Gar 

 nivora in the Proceedings of the Zoological Society for 1869. 



