170 Description of the Plates. 



this and other Rodents^ is concealed by the large external 

 ear. 



./. Part of Harderian gland, which discharges its secretion by 

 a duct opening under the rudimentary third eyelid or nicti- 

 tating membrane. This gland is found in most mammals, 

 with the exception of Chiroptera and Simiadae. 



g. Intra-orbital portion of lachrymal gland. Its duct joins that 

 of a second portion of the lachrymal gland [g), which lies 

 without the orbit. 



/. Extra-orbital portion of lachrymal gland, lying upon the 

 masseter muscle, and sending a duct with some glandular 

 tissue inlaid in its walls to enter the orbit at its posterior 

 angle, and receive the duct of the intra-orbital portion [g] . 



h. Cerebral hemisphere of right side. The external surface 

 of the two hemispheres is not convoluted ; at their poste- 

 rior aspect the longitudinal venous sinus is seen to divide 

 into the two lateral sinuses. A small triangular portion 

 of the large cerebellum comes into view at this point ; 

 the sinuses prevent the mesencephalon or corpora quadri- 

 gemina from being seen. 



i. Vagina. 



j. Parotid gland. Its ducts are seen to converge from its 

 constituent lobules, which are loosely aggregated from the 

 neighbourhood of the ear to that of the acromion, and to 

 cross, when united, the ramifications into which the motor 

 nerve of the facial muscles is seen to break up. The buccal 

 pouch is wanting in the true Mures, but some lymphatic 

 glands have been removed from the space between the 

 masseter muscle and the parotid gland. 



k. Portion of 'hibernating gland j^ a gland found in many 

 Rodentia, Chiroptera, and Insectivora, and spreading in 

 them into the axillary, the nuchal, the thoracic, and 

 occasionally even into the abdominal regions. 



I. Submaxillary gland and duct. 



m. Heart; the line ends upon the left ventricle. The apex of 

 the heart is not turned so much to the left as in man and 

 in some of the lower mammals, as, for examj)le, the mole. 

 The fold immediately below the point where the line abuts 

 upon the ventricle is formed by the cut edge of the 



