Miscellaneous. 71 



present I know no geuus with whicli it could be identified. It is 

 a curious thing to find such numerous and varied reptiles in the 

 Primary formations, which for a long time seemed to paliBontolo- 

 gists to be almost destitute of them. The discovery in the Permian 

 of a highly organized reptile like StereoracJiis, or those lately 

 indicated in North America by Prof. Cope, leads us to expect others ; 

 these animals are so far from the initial state of reptiles to lead us 

 to suppose that before them there were many generations of ances- 

 tors, and that some day, no doubt, we shall meet with their remains 

 even in the Devonian. — Comptes Bendus, Oct. 18, 1880, p. 669. 



A new Genus of Rodents from Algeria. 



M. Ferdinand Lataste has recently described a remarkable Rodent, 

 which he obtained in the Algerian Sahara, as the type of a new 

 genus of Muridoe, which he names Pachyuromys. It belongs to the 

 subfamily Gerbillinre ; and its most striking external character is its 

 tail, which is short, claviform, greatly swollen, and apparently 

 naked, its minute annulations and fine white hairs not concealing 

 the rosy tint of the skin in the living animal. Still more remarkable 

 is the structure of its skull, in which the auditory bulliB are so 

 greatly developed behind that they are only separated by a groove, 

 about 5 millims. in depth, at the bottom of which lies the foramen 

 magnum. Mr. Alston informs M. Lataste that such a development 

 of the bullae, both in their tympanic and more especially in their 

 mastoid portions, is not met with in any genus of Muridae with which 

 he is acquainted, and that a parallel can only be found in the Geo- 

 myidae, in the North- American geuus Dipodomys. 



Pachyuromys Duprasi, of which M. Lataste possesses several 

 living specimens, is a small animal, measuring about 100 millims. 

 in length of head and body, and 40 millims. in that of the tail ; 

 the upper parts are fawn-colour, the lower pure white. Its dis- 

 coverer promises a more detailed description, with figures of the 

 animal and its skull and observations on its habits. — ' La Natara- 

 liste; ii. pp. 313-315 (Nov. 15, 1880). 



Researches on the Comparative Anatomy of the Nervous System in 

 the different Orders of the Class of Insects. By M. E. Brandt. 



In 1879 I had the honour of bringing before the Academy my 

 investigations upon the nervous system of insects*. The present 

 note contains the principal results of my comparative researches 

 upon the nervous system in the diff'erent orders of the class Insecta. 



The nervous system of the Coleoptera has been studied in a great 

 many representatives of various families by M. E. Blanchard t. 

 This naturalist is the only one who has studied it as a whole ; and 



* Comptes Rendus, tome Ixxxix. pp. 475-477. 

 t Ann. Sci. Nat. 8'^ ser. tome v. (1846). 



