308 ANATOMY OF VERTEBRATES. 



branous floor of the mouth. This modification of * Wharton's 

 duct ' appears to be unique. The large size of the glands and 

 the mode in which the secretion is spread over the floor of the 

 mouth relate to the lubrification of the long, slender, and exten- 

 sible tongue, and to its fitness as an instrument for obtaining the 

 insect food of the spiny Monotreme. 



The salivary glands in the carnivorous Dasyures consist of a 

 small parotid and a large submaxillary gland on each side. They 

 do not agree with the dogs in having the zygomatic glands. The 

 submaxillary is placed in front of the neck, so that its duct passes 

 on the dermal side of the tendon of the biventer maxilla, and 

 terminates half an inch from the symphysis menti. There is 

 a thick row of labial glands along the lower lip. The Opossums 

 and Bandicoots present a similar salivary system. In the Pha- 

 langista vulpina there is a sublingual gland on each side of a firm 

 texture, about one inch in length and three lines broad ; a 

 roundish submaxillary gland about the size of a hazel-nut ; and a 

 broad and flat parotid, larger than in the entomophagous or sar- 

 cophagous Marsupials. The parotid glands are relatively larger 

 in the Koala, in which the duct takes the usual course over the 

 masseter and enters the mouth opposite the third true molar, 

 counting backwards. In the Wombat I found the parotid glands 

 very thin, situated upon both the outer and inner side of the 

 broad posterior portion of the lower jaw; the duct passed directly 

 upwards and outwards to the insertion of the sterno-cleido-mas- 

 toideus ; here it was buried in the cellular substance anterior to 

 that muscle, then turned over the ramus of the jaw, and, pur- 

 suing a somewhat tortuous course over the masseter, entered the 

 mouth just anterior to the edge of the buccinator. The sub- 

 maxiilary glands were each about the size of a walnut ; their 

 ducts terminated as usual on each side of the fraenum line-use. In 



o 



ihe great Kangaroo the parotid is very large, extending from 

 below the auditory meatus three or four inches down the neck : 

 In the Potoroos it reaches as far as the clavicle. In both genera 

 this gland is separated from the submaxillary gland by the sub- 

 maxillary vein. The sublingual glands are elongate, but of mo- 

 derate size. The tonsils are small in all the Marsupials, but are 

 not represented in the carnivorous species, as in the placenta! 

 Ferag, by simple glandular pouches at the sides of the fauces ; for 

 example, they consist of an oblong glandular body on each side 

 in the Dasyurus macrurus. 



In Rodents, as in Marsupials, the proportions of the parotid and 

 submaxillary differ according to the nature of the food. In the 



