58G MONOGRAPHS OF NORTH AMERICAN RODENTIA. 



long, suspends the hyoid from the back partofthe skull; and there are other 

 shorter, but still well-developed, "cornua". 



The salivary glands arc of enormous size.* On removal of the skin, 

 these glands present mosl conspicuously as a great mass across the throat, 

 completely filling the space between the jaw and the thorax, and between 

 the corner of the skull and point of the shoulder to the general contour of 

 the body at this part, and dipping deep behind and above the angle of the 

 skull, where it lies against the base of the skull. It is this glandular mass 

 that largely contributes to lack of distinction of neck observable in life, and to 

 the rendering of the circumferential measurement of the head behind the 

 ears as great as that of the body behind the shoulders f The two lateral 

 glands, which meet, but do not fuse, on the middle line of the throat, are the 

 parotids. Excluding the deep-seated portion beneath the mastoid and audi- 

 tory bullae, the glands form a flattened mass of irregular shape, the posterior 

 border adapted to the contour of the shoulder and thorax, the anterior simi- 

 larly fitted to the jaw. The duct proceeds from the anterior border, from a 

 point opposite the angle of the jaw, and lies superficial upon the masseter, 

 running forward along the middle of the mandibular part of this muscle, to 

 empty in the mouth near the commissure of the lips. Lying deep-seated, 

 covered by the mass just described, is found another pair of salivary glands, 

 perfectly distinct, about three quarters of an inch long, of a flattened amyg- 

 daloid shape. These are the submaxillaries ; they are in relation with the 

 muscles of the root of the tongue and inner border of the jaw, and the duct 

 appears to open on the side of the tongue near its base. J 



The oesophagus, measuring about five inches in length, is a simple tube, 

 of uniform small calibre, peculiar in no respect ; it pierces the stomach at a. 

 point midway between the pyloric and cardiac ends. 



The stomach, undistended and lying smoothly, flat on its side, appears 

 like a thick V, or still more like the conventional heart (on a pack of playing 

 cards for example"), though with gently rounded angle, and with longer upper 

 ends and deeper emargination than those of the figure just suggested. The 



•Apparently much as in the Beaver, and further indicating affinity between Haplodon and Castor. 

 The salivary glands " are enormous in the Beaver, extending from before the ears forward and downward 

 to contact with the submaxillaries, which are about one-twentieth their size ; the whole forming a sort 

 of glandular collar". — (OWEN, Comp. Auat. and Phys. Vert, iii, 390.) 



tThe largo mass of nuchal muscles on the back of the neck make the line from the occipital creBt 

 to the shoulders straight. 



t There is a large lachrymal gland. The eye-boll is very diminutive, about an eighth of an inch in 

 diameter — it could easily be inserted into the meatus of the ear. 



