n€2v Mammals from British Ntw Gumea. 71 



very woolly. Ear-conclies practically aborted, a mere rudi- 

 nicnf, 1-2 mm. in length, being all that is left of them. 

 Whi.skers not so thick or long as in tlie allied forms. 

 Fingers free, toes rather more broadly webbed than in 

 Ilydromys ; claws, both fore and hind, small, delicate, strongly 

 curved ; hind feet brond, more twisted than in Ilydromys, 

 those of Parahydromys * being less so ; solf-pads broa'l and 

 smooth, a large part of the elongate hallucal pad visible in an 

 upper view of the foot. Tail provided with a strongly 

 marked swimming-fringe below, formed of hairs about 8 mm. 

 in length, the fringe bifurcating into two lateral ridges on 

 the proximal inch of the short-haired part of tlie tail. 



Skull with a proportionally short slender face and very 

 large, smoothly rounded, broad and low brain-case. The 

 distance from the supraorbital foramina to the occiput is 

 tiierefore greater instead of less than tliat to the tip of 

 the muzzle. Nasal and interorbital region slightly built, not 

 broadly swollen as in Parahydromys. Cranial ridges 

 practically absent. Interparietal sutures almost obsolete in 

 the type, which is an old specimen. Structure of ante- 

 orbita! and palatal foramina as in Ilydromys, the latter not 

 so far forward as in Parahydromys. Bullne very small, in 

 correlation witii the abortion of the external ear-conches. 



Dentition as in Ilydromys. Upper incisors narrow, con- 

 siderably bevelled laterally. Molars small in proportion to 

 the size of the animal ; in structure like those of Ilydromys 

 except that the laminjc are more directly transverse and the 

 middle lamina of m' is scarcely broadened internally. 



Type Crossomys Moncktoni. 



This beautiful animal forms a most striking new genus, 

 and .Mr. Monckton is to be congratulated on its discovery. 

 In specialization for an aquatic life it far surpasses Ilydromys, 

 as indicated by its woolly fur, aborted ear-conches, twisted 

 hind feet, and fringed tail, in which last character it re- 

 sembles the European water-shrew (Neomys, long known 

 as Crossopus). Indeed in the accumulation of these characters 

 it stands at the head of all rodents, for while Fiber has 

 an even more specialized tail and the same fur and feet, it has 

 letained its ear-conches. Perha[)s the nearest analogue to 



* Described as Linwomi/s, Ann. & Mapf. N. H. (7) xvii. p. 32.') (lOO(i). 

 Tliis name being- preoccupied (iMearns, l'JO.5) the genus was given (Zool. 

 Anz. xx.\. p. 32ti, I'JUG) the clumsy name of Parahydronujs by I'oche, 

 to whom a perusal of page 14 line 10 of the Stricklaudiau Code of 

 Nomenclature (1863) is to be reccmimended. My own substituted name 

 of Drosomys (P. Biol. Soc, Wash. xix. p. ll^O, litUG) was a few mouths 

 later in date. 



