FfiOM THE PHILIPPINE ISLANDS. 393 



Owing to the remarkable modification in its colour, quite unique among Muridse, 

 this animal may be looked upon as one of the most striking of all Mr. Whitehead's 

 discoveries. Scientifically, it shares with Cehenomys and Crunomys the interest 

 attaching to the occurrence of the subfamily Hydromyinee away from the Australian 

 region, to which the only two previously known genera are confined. No member of 

 the group has as yet been found in any of the intervening islands, although it is possible 

 that when the higher mountains of the archipelago are more thoroughly explored other 

 forms referable to the subfamily will also be found to occur there. 



"This handsome Eat was obtained on the summit of Monte Data. It is said by the 

 natives to feed on sweet potatoes and grass, and to frequent the neighbourhood of their 

 plantations. Chrotomys is also met with at almost the sea-level, as I saw in Manila a 

 specimen obtained in the Forest of Tarlao in Central Luzon to the north of that city. 



" Listribution. Probably throughout Luzon." — J. VV. 



Crunomys 1, g, n. 



External characters, apparently much as in Xeromys, though the number of mammfe 

 and sole-pads cannot at present be determined. Fur thickly mingled with spines. Ears 

 i-hort and rounded. Hallux with a claw. Tail rather short, thinly haired, apparently 

 flattened at end, but this appearance may be simply due to contraction in drying. 



Skull (PI. XXXV. fig. 6J with the peculiar shape characteristic of many Water- 

 Rodents, such as Hydromys, Ichthyomys, and others; low, flattened, its frontal profile 

 concave. Nasals long, overhanging the incisors in front. Interorbital region broad, 

 its edges with scarcely a trace of beading. Interparietal large. General shape 

 of anteorbital foramina almost exactly as in Chrotomys, the outer plate not produced 

 forward. Incisive fissure minute. Anterior palatine foramina short. Posterior edge 

 of palate just level with the hinder edge of m.^. 



Molars (PI. XXXV. fig. 5) much worn in the only specimen, so that it is difficult to 

 make out their exact structure. It is, however, clear that they are more murine in 

 structure than is the case with the other members of the Hydromyinee; in m.i the 

 anterior lamina is oblique just as in the other genera of the Hydromyinte, but in other 

 respects might almost be that of Mus itself. M? is also very murine, having a small 

 antero-internal cusp, along middle lamina, and a mesial circular one posteriorly; m.^ is 

 subcircular, with a small antero-internal cusp. Below, on the other hand, the teeth are 

 not unlike those of Chrotomys, except that m 3 is bilaminate as in Mus, a difference that 

 one would expect to occur owing to the greater development of this tooth in Crunomys. 



Type. Crunomys jallax. 



This genus is most interesting from an evolutionary point of view, for it adds 



D^ 



' upmi os^ a well-spring ; kpoi" ai', torrents or streams. 

 VOL. XIV. — PART vr. No. 3. — June, 1898. 3 F 



