474 PHILIPPINE RODENTS chap. 



Sub-Fam. 2. Hydromyinae. — The genus Hydromys} of which 

 there are several species, the best known being H. chrysogaster, 

 is an exclusively Australian form, and is aquatic in habit. It 

 is a foot or so in length, and has a fairly long tail. The fore- 

 and hind-limbs are webbed, in correspondence with its habits. 

 The Australian Water-Eat is black, with an admixture of golden- 

 coloured hairs dorsally and golden colour below, with a lighter 

 median stripe. The thumb is small, and the webbing of the 

 hands is not so marked as is that of the feet. The molars are 

 only two in each half of each jaw. The caecum is rather small, 

 the measurements of the alimentary canal being : small intestine, 

 895 mm. ; large intestine, 278 mm. ; caecum, 70 nun. Allied to 

 the last is Xeromys, a genus which is also Australian, but limited 

 to Queensland. It has been established by Mr. Thomas,- who 

 discovered that it has the same reduced formula as Hydromys. 

 Xeromys, however, is not an aquatic animal, and has un webbed 

 feet. 



In the Luzon highlands Mr. Whitehead has discovered, and 

 Mr. Thomas quite recently described,^ a number of peculiar 

 Eodents. Of these the genera Chrotomys, Celaenomys, and Cru- 

 7iomys are allied to the Australian and New Guinea Hydromys. 



Chrototnys whitelteadi is unusual among Muridae, in its 

 coloration being marked by a pale stripe down the Ijack. The 

 creature is the size of the Black Eat (Mus rattus). It is terres- 

 trial not aquatic in habit, in spite of its likeness to Hydromys. 

 The molars, however, are |. 



Crunomys fallax is more like Hydromys. It has, however, 

 three molars, as in the last genus. But the skull has the 

 flattened form characteristic of Hydromys as opposed to Mus. 



Like Batomys, Celaenomys silaceus is also somewhat inter- 

 mediate lietween Hydromys and Mus. It is described as very 

 Shrew-like in appearance, and has a very pointed muzzle. Its 

 habits Mr. Whiteliead is " quite unable even to guess at." Like 

 Hydromys and Xeromys this Eodent has but two molars. 



Sub-Fam. 3. Rhynchomyinae. — The genus Bhynchomys, con- 

 taining l)ut one species, Bh. sorkioides (of Thomas), is also, as both 

 its generic and specific names imply, a somewhat Shrew-like form in 

 external aspect. The skull, too, is Insectivore-like in its elonga- 



^ For anatomy see Windle, Proc. Zool. Soc. 1887, p. 5-3. 

 - Proc. Zool. Soc. 1889, p. 247. ^ Tra/ns. Zool. Soc. xiv. 1898, p. 377. 



