ticw Mammals from British New Guinea. 71 



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

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

 Whiskers not so thick or long as in the allied forms. 

 Fingers free, toes rather more broadly webbed than in 

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

 curved ; hind feet broad, more twisted than in Hydromys, 

 tliose of Parahydromys * being less so ; sole-pads broad and 

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

 upper view of the foot. Tail provided with a strongly 

 marked swiniming-friiioe below, formed of hairs about 8 mm. 

 m length, the fringe bifurcating into two lateral ridges on 

 the proximal inch of tbe short-haired part of the 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 

 therefore greater instead of less than that to the tip of 

 tlie 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- 

 orbital and palatal foramina as in Hydromys^ the latter not 

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

 correlation with the abortion of the external ear-conches. 



Dentition as in Hydromys. Upper incisors narrow, con- 

 siderably bevelled laterally. Molars small in proportion to 

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

 except that the lamime are more directly transverse and the 

 middle lamina of m^ is scarcely broadened internally. 



1'ype Crossomys Moncktoni. 



This beautiful animal forms a most striking new geims, 

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

 In specialization for an aquatic life it far surpasses Hydromys, 

 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 wliile Fiber has 

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

 letained its ear-conches. Perhaps the nearest analogue to 



* Described as Limnomijs, Ann. & Mag. N. H. (7) xvii. p. 325 (1900). 

 This name being preoccupied (Mearns, l!»0o) tbe genus was given (Zool. 

 Anz. XXX. p. 326, 1906) the clumsy name of Parahydromys by Poche, 

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

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

 of Drosomys (P. Biol. Soc. Wash. xix. p. 199, 1906) was a few months 

 later in date. 



