428 Zoological Society. 



tion in bis letter to the differences observed in tlie sexes of this ani- 

 mal, the female being considerably smaller than the male, and re- 

 markable for having the tail very thick and fleshy. It is known to 

 the natives by the names ' Comadrejo' and ' Llaca.' " 



The following is Mr. Waterhouse's description of the new species 

 of Mus (which he i)laces in the section Hesperomys) contained in the 

 collection : — 



Hesperomys megalonyx. Hesp. supra cinerascenti-fiiscus, subtus 

 cinereo-ulbus ; auribus mediocribus ; pedibus anticis itnguibus mag- 

 nis attnatis ; caudd brevi, pills viimiiis obsitd. ^^p Yiv\. 



Longitudo ab apice rostri ad caudae basin .... 4 4 



cai/d(c 1 6 



auribus . . 3^ 



tarsi digitorumque 11^ 



ab apice rostri ad basin auris .... 1 2^ 



Hab. Chile. 



This Uttle mouse evidently belongs to the genus Hesperomys, but 

 it differs from any species hitherto described in having stronger fore- 

 feet, and these furnished with long claws, exceeding the toes in 

 length. The inner toe or thumb is furnished with a distinct pointed 

 claw, 'llie fur is very soft, and in the upper parts of the body nearly 

 of a uniform grey-brown tint, though the hairs of the ordinary fur 

 are annulated with pale brown ; at the base these hairs are of a deep 

 slate-grey colour. The under parts of the body are grey-white, but 

 the hairs are deepish grey at the root, and on the chest there is a 

 brownish mark. The chin is white ; the feet are pale brown, but the 

 hairs on the toes are dirty white. The tail is clothed with short 

 brown hairs. The ears, which are rather small, are well-clothed with 

 moderately long hairs, and these are variegated with pale brown and 

 dusky ; they are much hidden by the long fur of the head. 



From j\Ir. Bridges' notes I learn that this little animal was found 

 near the margin of the Lake of Quiutero. 



Mr. Waterhouse also characterized a new species of Octodon con- 

 tained in a former collection sent home by Mr. Bridges : — 



Octodon Bridgesii. Oct. corpore suprh flavesccnti-fusco nigroque 

 penicillato ; subtus flavescente ; pedibus albis ; auribus magnis 

 postice emarginatis ; caudd, quoad longiludinem, corpus fer'k 

 (Bquante, nigra, szibttis sordide albd, dimidio apicali pilis longis 

 vesttta. m^(, jjp^ y,^p_ ]jjj_ 



Longitudo ab apice rostri ad caudae basin . . 8 vel 8 6 



caudcE 5 6 „ 5 8 



tarsi digitorumque 1 6\ ,, 1 6|^ 



auris Q\ ,, 6|- 



Hab. Chile. 



The general hue of this animal is brownish, a tint produced by 

 the admixture of brownish ochre and black : the hairs of the fur are 

 deep slate-grey next the skin, and on the back black externally, but 

 most of them broadly annulated with deej) ochre towards the point ; 



