62 



DR. B. C. A. WINDLE ON THE 



[Feb. 1, 



excessively small points, each of which fits into a corresponding 

 depression in the alveolus {vide fig. 6, c). 



The second upper molar looks like one of the divisions of the 

 first with an additional cusp attached to its antero-iiiternal corner. 

 It has three roots, two posterior with their surfaces j)laced external and 

 internal, and one anterior with its surfaces anterior and posterior. The 



Fig. 6. 



Eydromys cliry&r,c;aster: «, lower jaw; t, iipj^er jaw ; c, upper molar (enlarged). 



Fig. 7. 



Stomach oi Hydromys chrysogaster : oe, cardiac orifice; py, pyloric orifice. 



lower incisors {vide figs. 5, 6, a) are of greater length (r55 cm.) and 

 of about the same breadth, but of less thickness (0"25cm. as compared 

 with 0"4 cm.) than the upper. Their power of approximation, due to 

 the mobility of the two halves of the inferior maxilla, has already been 



