Transactions of the Linnean Society. 487 



and in the Rasores, in the Fer« and in the Glires ; and the diminished 

 power of the fore, and increased strength of the hinder, extremities, ex- 

 ists in the Rasores and in the JVatatores, in the Glires and in the Ceta- 

 cea : groups not immediately following each other in the direct series of 

 affinity, but yet having a mutual resemblance in remarkable and import- 

 ant particulars. 



A second truly valuable contribution to the natural history of the Mam' 

 malia is furnished in the " Description of the Mammary Organs of the 

 " Kangaroo," by John Morgan, Esq., F.L.S., in which the fullest light 

 is thrown on that very interesting subject of physiological enquiry, the 

 means by which nature has provided for the nourishment and growth of 

 the young of Marsupial animals, while yet remaining in the maternal 

 pouch. By the anatomical examinations of which the results are here 

 described in detail, Mr. Morgan has succeeded in demonstrating in the 

 most satisfactory manner the existence of structures adapted for injecting 

 the milk into the alimentary canal of the young while it is yet too feeble 

 and imperfectly organised itself to extract the nutritious fluid, and has 

 shown to what extent each of the contrivances which he has pointed out 

 is capable of being rendered subservient to the end proposed. He has 

 also explained the very curious differences which exist between the state 

 of these organs in the unimpregnated and in the suckling animal, and has 

 completely elucidated almost every point immediately connected with the 

 subject of his enquiry. Of this excellent paper so full an analysis has 

 already been given at page 127 of our present volume as to render it un- 

 necessary for us again to enter into details respecting its contents, which 

 are admirably illustrated by an extensive series of well executed engrav- 

 ings exhibiting the anatomy of the whole of the organs described. 



A Contribution to our native Fauna is furnished by the Rev. Leonard 

 Jenyns, F.L.S., in a paper entitled, " The distinctive Characters of two 

 " British Species of Plecotus, supposed to have been confounded under 

 " the name of Long-eared Bat." Its principal object is to describe a 

 Bat to which the authour has applied the name of Plecotus brevimanus, 

 and which he regards as specifically distinct from the Plec. auritus, Geoff. 

 The chief differential characteristics are thus expressed: "1. Plec. auritus; 

 " Plec. vellere fusco-griseo, subtiis aliquant6 pallidiori ; auriculis oblon- 

 " gis, capite plus duplo longioribus ; trago ovato-lauceolato ; cauda 



