86 ^Ir. 0. Thomas on a new 



IX. — A new Aquatic Genus of IMurida^ discovered hj 

 Consul L. Soderstr'um in Ecuador. By Oldfield ThOMAS. 



Among a further consignment of small mammals which the 

 British l\Iuseum owes to the generosity of Consul L. Soder- 

 stiiim, of Quito, there occurs a most interesting new form, 

 ilie type of tiie following description : — 



Anotomys, gen. nov. 



External characters as in Ichthyomys^ but ear-con.ch quite 

 rudimentary and the ear-opening itself a mere minute slit. 

 Fur exceedingly rich and velvety, almost wholly composed 

 of wool-hairs. Feet strongly fimbriated. 



Skull with the brain-case smooth, round, and inflated, like 

 that of a young non-aquatic Murine, not flattened as in 

 Ichthyomys. Muzzle set on in a peculiar manner, appearing 

 to be bent upwards owing to the strong angle at which its 

 upper profile meets the marked rise of the frontal, and to this 

 jirotile continuing perfectly straight anteriorly without any 

 descent towards the tip of the nasals. Nasal opening not 

 slantmg backwards in lateral view, but practically vertical, 

 the tip of the nasals projecting in front of the main part of 

 the premaxillre, but in turn just surpassed by the unusually 

 projecting gnathic point between the incisors ; in front view 

 the opening is high and narrow, approaching "guttate" of 

 Ridgway, while in Ichthyomys it is nearly " deltoid " (the 

 point, of course, downwards in each case). Anteorbital 

 Ibramina essentially as in Ichthyomys, or even more open ; 

 the anterior zygoma-root, both above and below, very slender 

 and delicate. Malars absent on both sides in the type, 

 possibly never ossified. Palatal foramina much broader 

 behind than in front, instead of being approximately parallel- 

 sided. Po-sterior palate less extended behind the molars. 



Incisors narrower and less specialized than in Ichthyomys, 

 the lower ones particularly narrow, with long slender points; 

 a marked laterally projecting incisive capsule over the root of 

 each upper incisor, in front of the anteorbital foramen. 

 Molars apparently as in Ichthyomys^ but much worn in the 

 only specimen. 



Type, A. leander. 



This genus is evidently closely allied to Ichthyomys^ but is 

 less specialized for an aquatic piscivorous life in some direc- 

 tions (shape of brain-case, structure of incisors), and more so 



