PROCEEDINGS 



OF THE 



ZOOLOGICAL SOCIETY OF LONDON. 



January 14, 1840. 

 William Yarrell, Esq.. V.P.. in the Chair. 



Mr. Ogilby exhibited the skull of the Mangabay Monkey (Cerco- 

 pithecus jrEthiops, Auct.), and called the attention of the members 

 present to the fact that this species, like the C.fuliginostis, differs 

 from other Cercopitheci in possessing a fifth tubercle to the last 

 molar of the lower jaw. 



Mr. Ogilby then commenced the reading of his paper entitled 

 " Monograph on the hollow-horned Ruminants." 



A variety of the common Htxre (Lepus timidus, Auct.), shot in 

 Susse;c, and presented to the Society by Augustus E. Fuller, Esq., 

 was exhibited : it differs chiefly in being of a smaller size, and in 

 having the fur somewhat mottled with whitish and in parts rust co- 

 lour. 



Mr. Waterhouse exhibited a new species of Rodent from the river 

 Gambia, and stated that he was indebted to Alexander Nasmyth, 

 Esq., for the loan of this curious animal, which constitutes a most 

 interesting link between the genera Mus and Cricetus : like the first 

 of these genera, it has a long scaly tail, but it resembles the Ham- 

 sters in possessing large cheek-pouches. In the number of its molar 

 teeth and the form of the skull it presents all the most common cha- 

 racters of the Muridce, as defined by Mr. Waterhouse in the Maga- 

 zine of Natural History*. 



The skull compared with that of the Common Rat (Mms decuma- 

 nus, Auct.) differs chiefly in having the nasal portioii more elongated : 

 the anterior root of the zygoma, as in that animal, is in the form of 

 a thin plate, but this plate is less extended in its antero-posterior 

 direction, is directed obliquely outwards and upwards, and leaves a 

 tolerably large and nearly round ant-orbital opening, thus differing 

 from the Common Rat, in which the lower portion of this opening 

 is in the form of a vertical slit : the zygomatic arch is less extended 

 in the longitudinal direction, the incisive foramina are much smaller, 

 and the auditory bullBe are rather smaller in proportion. The molar 

 teeth are rooted ; the foremost of these teeth in either jaw is the 



* Vol. iii. p. 275. 

 Nos. LXXXV. & LXXXVI. — Proceedings of Zoological Society. 



/O 



