472 



COLLEGE ZOOLOGY 



Olfactory bulb 



Olfacfory tract I 

 OpHc II 



Optic chiasma 

 Cerebrum-- — 

 Pituitary 



Oculomotor III 

 Trochlear IV 

 Pons 



Trigeminal V 



Facial VII 



Auditory VIII 

 Abducens VI 

 Vermis 

 Cerebellum 



Glossopharyngeal IX 

 Vagus X 

 Medulla 



Hypoglossal XII 

 Spinal nerve I 

 Accessory XI- 

 Nerve (spinal) cord 



DORSAL 



VENTRAL 



Figure 344. The brain of a cat shows the complexity of the brain which characterizes mam- 

 mals and is doubtless one of the reasons why they have become a dominant group. 



like the ears of amphibians, reptiles, and 

 birds, which have only one bone, the col- 

 umella. The cochlea of the inner ear is 

 spirally coiled and not simply curved as in 

 the pigeon. The nasal cavities are large, 

 indicating a highly developed sense of smell. 



Endocrine glands 



In the cat the ductless glands consist of 

 the thyroid, parathyroids, pituitary, islets 

 of Langerhans, adrenals, and gonads. Their 

 functions, much like other mammals, are 

 discussed in Chapter 33. 



Reproductive system 



The two testes of the male lie in oval 

 pouches of skin called scrotal sacs, one on 

 either side of the copulatory organ, the 

 penis (Fig. 343). The sperms pass from 

 each testis into minute convoluted tubes 

 called the epididymis; they then enter the 

 sperm duct, or vas deferens, which leads into 

 the abdominal cavity and opens into the 

 urethra. During copulation the sperms pass 



into the urethra and are transferred to the 

 female by the penis. At the base of the 

 urethra is the prostate gland; and just pos- 

 terior to the prostate is a pair of bulboure- 

 thral (Cowper's) glands. The secretions 

 from these glands are added to the sperms, 

 making the seminal mass more fluid and 

 neutralizing the acidity resulting from the 

 passage of urine through the urethra. 



The two ovaries of the female are ovoid 

 bodies exhibiting small, rounded projections 

 on the surface; these are the outlines of the 

 Graafian follicles, each of which contains 

 an egg or ovum. Each ovary lies lateral to 

 the ostium, which opens into a small 

 oviduct. The latter is continued posteriorly 

 as a thick-walled uterus. The two uteri unite 

 medially to form the body of the uterus 

 from which the vagina extends to the uro- 

 genital opening. On the ventral wall of the 

 vestibule lies a small rodlike body, the 

 clitoris, which corresponds to the penis of 

 the male. The eggs are fertilized while in 

 the oviduct and then pass to the uterus, 

 where development takes place. 



