512 ON SOME MAMMALS FROM ECUADOR, [Apr. 21, 
Genus PuDUA. 
Size very small. Hair coarse and brittle. Horns simple spikes. 
Metatarsal and metacarpal joints short. ‘Tail very short or 
wanting. Ears short and rounded. No turn in the hair of the 
face. Infranarial portion of the rhinarium deep. Canines absent. 
Middle pair of incisors not broadly spatulate. Ascending rami of 
the premaxille may or may not reach the nasals. Lachrymal pit 
oval and very deep. Auditory bulle not inflated. Ectocuneiform 
and navicular-cuboid bones united. Metatarsal bone not twice 
and metacarpal bone not 14 the length of the upper molar series. 
2. IcHTHYOMYS SODERSTROMI, spn. (Plate XX.) 
The general colour of the whole of the upper parts dark olive- 
brown, the main coat of black-brown fur being narrowly tipped 
or having a subterminal band of dull yellow; thickly interspersed 
are longer shining black hairs, these being longest on the hind 
quarters, where they are broadly tipped with silvery white. On 
parting the fur the only colour found is soft grey, all the main fur 
having long fine footstalks, so that the whole coat below the 
surface, save for the few coarse shining hairs, is of a uniformly 
fine texture and very dense. Ears same colour as the head. The 
tail, which is thickly haired, is entirely dark brown or black, the 
fringe of longer hairs on the lower side being of absolutely the 
same colour; the fore feet are covered with short black hairs, with 
a few longer white hairs at the base of the claws; the hind feet 
are black above and below, excepting a few grey hairs round the 
claws and on the inner side of the tarsus the fringe of stiff hairs 
is white; the whole of the underparts from the chin to the vent 
are dirty white, the under-fur being grey and the outer silvery 
white; the inner sides of the fore and hind limbs are of a more 
pure white; the whiskers are black or white according to the 
position in which they grow on the face, those placed high up 
being black, and there are a few particoloured ones in the middle 
growth. Palate-ridges 3-3. _Mamme 6: one pair on the breast 
and two pairs on the belly. 
Measurements of type skin( 9 ad. no. 96, i. 28.2,in Brit. Mus.):— 
Head and body 180 mm. Tail 150mm. Hind foot 31:5 mm. 
Ear 8-5 mm. Forearm and hand 31 mm. 
Skull—Greatest length 31:°5 mm.; greatest breadth 16 mm. 
Nasals—length 12 mm.; breadth 3°9 mm.  Intertemporal— 
breadth 4:9 mm. Interparietal—length 2 mm.; breadth 3 mm. 
Basal—length 29 mm. ; basi-facial 18-5 mm.; basi-cranial 10°5 mm. 
Palate—length 16 mm.; breadth, outside a6 mm., inside 1B mm.; 
diastema 8°5 mm.; foramina 5°5 mm. Upper molar series— 
length 4:3 mm. Lower jaw—condyle to incisor tips 20°56 mm. 
Hab. Rio Machangara, Ecuador. ‘“ Water Rat. Feb. 1895” 
(L.-89: 
The skull is remarkably delicate and fragile for such an old 
animal (the teeth being much worn), and is smaller and narrower 
