Zoological Society. 5^5 



The average number of malformations, according to Mr. Buck- 

 nell's experience, was not more than five in a thousand ; though in 

 Egypt, it was stated, malformations were extremely common in the 

 artificial process of incubation. He attributed this circumstance to 

 an excess of heat, and generally found it to affect the toes and ex- 

 tremities ; sometimes also the muscles of the neck. 



A general conversation afterwards took place on this subject, 

 during which much interesting and valuable information was ex- 

 tracted, with regard to the period and circumstances of the incuba- 

 tion. 



June 25. — Mr. Waterhouse read a paper on a new species of Ro- 

 dent which had been sent from the island of Luzon, one of the 

 Philippines, by Hugh Cuming, Esq., Corresponding Member, 



In general appearance this Rodent might be mistaken for a species 

 of Capromys ; in size it is about equal to the C. Fournieri ; the gene- 

 ral characters of the skull and dentition, however, indicate that its 

 affinity is with the Muridoe. 



" The skull, compared with that of the common Rat, differs in 

 being of a more ovate form, the occipital portion being somewhat 

 elongated, and considerably contracted ; the width between the or- 

 bits is comparatively great ; and behind the orbits the frontal bones 

 are expanded, and join with the temporal to form a distinct post- 

 orbital process. The interparietal bone, instead of being transverse, 

 is almost circular. The auditory bullae are very small. The inter- 

 dental portion of the palate is slightly contracted in front, so that 

 the molares diverge posteriorly ; the rami of the lower jaw are less 

 deeply emarginated behind, the coronoid portion is smaller, and the 

 descending ramus is broader and rounded ; the symphysis menti 

 is of considerable extent. The incisor teeth are less compressed and 

 less deep from front to back. The molar teeth are of a more simple 

 structure ; the anterior molar of the upper jaw consists of three 

 transverse lobes, and the second and third consist each of two 

 transverse lobes. In the lower jaw the anterior molar consists of 

 four lobes, a small rounded lobe in front, followed by two transverse 

 lobes, of which the anterior one is the smaller, and finally a small 

 transverse posterior lobe ; the second molar consists of two equal 

 transverse lobes, and a small lobe behind them ; the last molar con- 

 sists of two simple transverse lobes." 



On account of the differences observable in the structure of the 

 teeth, and form of the skull, combined with the hairy nature of the 

 tail and ears, Mr. Waterhouse regarded this animal as constituting a 

 sub-genus, and proposed for it the name of Phlceomys', this name 

 being suggested by the habit of the animal, which Mr. Cuming 

 (after whom the species is named) states, feeds chiefly on the bark of 

 trees. It may be thus characterized : 



Mus (Phlceomys) Cumingi. M. vellere setose, suberecto, pilis la- 



nuginosis intermixtis ; awrihus mediocribus extiis pilis longis 



obsitis ; mystacibus crebris et perlongis ; pedibus permagnis et 



latis, subtiis nudis ; caudd mediocri, pilis rigidis et longis {ad 



' 4>Xoi6s, bark {(pXoiw, to decorticate), and Mi)s. 



Phil, Mag. S. 3. Vol. 15. No. 99. Supplement, 1839. 2 N 



