486 Analytical Notices of Books 



mates is universally acknowledged, and the transition may be made either 

 through the Bats, which by Linnaeus were arranged with the latter, and 

 by M. Cuvier with the former ; or through Didelphis, placed among the 

 Fer<s by Linnaeus, and connected with Lemur by Schreber and Illiger, 

 The progression of affinity has in this manner brought us back to the point 

 from which we departed, and the group is therefore a natural one. 



The nearest approach of the Mammalia to Birds exists, according to 

 Mr. MacLeay, among the Glires, which make several attempts, as it were, 

 to attain the structure of the feathered class. Dipus gives us the legs and 

 feet of a bird; Sciurus, the feathers; Hystrix, the quills; and Pieromys, 

 the wings, of a bird. The only other flying Mammalia are the Petauri, 

 which are so nearly allied to Pteromys as not to require in this enquiry 

 to be separated from it; and the Bats, which are entirely unconnected 

 with Birds in all their organs excepting those immediately subservient to 

 the purpose of sustaining them in the air. Among the Birds the near- 

 est approach to Mammalia is made by the Struthionidce, a position which 

 may be considered as having been already repeatedly proved. 



In the brief outhne which we have attempted of this most curious and 

 valuable paper, we have been compelled to limit our analysis to a bare 

 enumeration of the leading views advanced by its authour, omitting al- 

 together the evidences adduced by him in support of them. We have 

 also been under the necessity of abstaining from noticing many interest- 

 ing remarks which are incidentally introduced, such as those which re- 

 late to the Marsupiata and Edentata, to the relation existing between 

 them and the ReptiHa, to the analogies exhibited by the Edentata to 

 genera among the Glires and the Insectivora, &c.; such as those again: 

 in which it is shown that as the five groups of Tnsessores represent, 

 as explained by Mr. Vigors, the five orders of Birds, so are they, and 

 consequently the orders, represented by the five groups of the Scanso- 

 res. For these we must refer to the paper itself, which we quit with 

 the single additional observation that in it Mr. MacLeay repeatedly in- 

 sists on a kind of relation hitherto little remarked on by him, that of 

 transultation ; which exists where the direct affinity of a group to that 

 immediately succeeding it being preserved, a marked resemblance is yet 

 found between it and that which is next but one in succession to it. Thus 

 the rounded y*acie« and the strength of jaws are met with in the Raptoresr 



