$12 MANUAL OF ZOOLOGY SECT. 



In the organs of special sense the following special 

 features are to be seen when a comparison is made with the 

 Pigeon. In the eye, the sclerotic is composed entirely of 

 dense fibrous tissue ; the pecten is absent. In the ear the 

 principal point of difference is in the special development 

 of the cochlea. This part of the membranous labyrinth, 

 instead of retaining the simple curved form which it presents 

 in the Bird, is coiled on itself in a close spiral of two and a 

 half turns. The special features of the middle ear with its 

 auditory ossicles have been already referred to. 



The kidneys are of somewhat compressed oval shape, 

 with a notch or hilus on the inner side. They are in 

 close contact with the dorsal wall of the abdominal cavity, 

 the right being slightly in advance of the left. To- 

 wards the hilus the tubules of the kidney converge to 

 open into a wide chamber the pelvis which forms the 

 dilated commencement of the ureter. When the kidney 

 is cut across, its substance is seen to be divided into a 

 central mass or medulla and a peripheral portion or cortex. 

 An adrenal (suprarenal] body lies in contact with the 

 anterior end of each kidney. The ureter (Fig. 287, ur.) 

 runs backwards to open, not into a cloaca, but directly 

 into the urinary bladder (/.). The latter is a pyriform sac 

 with elastic, muscular walls which vary in thickness according 

 as the organ is dilated or contracted. In the male the 

 openings of the ureters are situated much nearer the 

 posterior narrower end or neck than in the female. 



In the male Rabbit the testes are oval bodies, which 

 in the young animal occupy a similar position to that 

 which they retain throughout life in the Pigeon, but which 

 as the animal approaches maturity pass backwards and 

 downwards until they come to lie each in a scrotal sac 

 situated at the side of the urinogenital opening. The 



