16 ANATOMY OF THE RABBIT 



commonly described as endocrine glands, which are not necessarily 

 epithelial in origin and of which the resemblance to ordinary glands 

 is often only a matter of superficial appearance and of the fact that 

 both secrete, i.e. produce special substances in their cells and dis- 

 charge them either on a free surface or towards the blood stream. 

 Most multicellular glands conform to one of two types, namely, 

 the tubular gland, in which the secreting portions are of uniform 

 calibre, and the acinous or alveolar gland, in which the secreting 

 portions are sacculated (Fig. 3). Both types occur in simple, little 

 branched, and greatly branched conditions (Figs. 3, 4), and the 

 tubules of the former type may be elongate and greatly coiled. 



Cutaneous glands of two types are commonly present in 

 mammals in association with the hairs, namely, sudoriferous or 

 sweat-glands, which are of the tubular type, and sebaceous glands, 

 which are of the acinous type and produce an oily secretion. In the 

 rabbit, glands are absent from the general surface, but are found in 

 special situations, as, for example, in connection with the hair. 



follicles of the lips, the internal surface of 

 the ear, and the external genital organs. 

 The inguinal glands comprise both tubular 

 and acinous portions. The mammary 

 glands of the female are greatly modified 

 cutaneous glands of the sudoriferous type. 

 Besides the mucus-secreting cells of the 

 general epithelium, the glands of the ali- 



FiG. 4. From a section of , . , . 



the parotid salivary gland of mcntary caual compHsc the important but 



the rabbit. A, Duct system , , , i i i r i n i 



in relation to body of gland: Icss elaborated glauds oi the Wall, such as 

 fntedobiiar duct" B° Three the gastrlc glands of the stomach ; and the 



individual acini, highly mag- ,, ,, ,, ..i- 1J 



nified. greatly elaborated, outstandmg glands 



which lie beyond the wall and are con- 

 nected with the interior of the canal only through their ducts. The 

 latter comprise the oral glands, the liver, and the pancreas. The 

 oral glands include chiefly the submaxillary, parotid, sublingual, 

 buccal, and infraorbital glands^conspicuous structures in the dis- 

 section of the surrounding portions of the head and neck. Their 

 ducts communicate with the cavity of the mouth. 



The secretion of the oral glands has important mechanical 

 functions in moistening the comminuted food in preparation for 



