474 PHILIPPINE RODENTS 



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. 

 Tlie Australian ^Vater-Rat is lilack, 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, 

 89 5 mm. ; large intestine, 278 mm. ; caeciim, 70 mm. Allied to 

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

 to <L»ueensland. 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 j\Ir. Whitehead has discovered, and 

 ]\Ir. Thomas quite recently described,^ a number of peculiar 

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

 noniys are allied to the Australian and New Guinea Hyd;romys. 



ClbTotomys whiteheadi is unusual among iluridae, in its 

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

 creature is the size of the Black Eat (If-us 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 dlaceus is also somewhat inter- 

 mediate between Hydromys and Mvs. It is described as very 

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

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

 Hydromys and Xeromys this Eodent has but two molars. 



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

 taining but one species. Eh. soricioides (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. 53. 

 ■' Proc. Zool. Soc. 1889, p. 217. ^ j'l-ans. Zool. Soc. xw. 1898, p. .377. 



