408 Mr. G. R. Waterhouse on the Classif cation of Mammalia. 



true molars are two in number, and sometimes not only assume 

 the quadi-ate form but the prickly crowns, and even the four 

 principal cusps as in Gymnura. In Mydaus (which is one of the 

 Mustelidce*) the single true molar is of a very different general 

 form, though the tubercles on its surface are somewhat acute : 

 neither of these cases, in my opinion, exhibits an approach of 

 direct affinity ; and that instance of a certain resemblance between 

 the Gymnura and the Ursida, just alluded to, it will be perceived, 

 affords another illustration of points discussed in this paper ; for 

 among the Ursida, that species which in the structm'c of its molar 

 teeth approaches more nearly to the Imectivora, is one which in 

 other points is most removed from that order, — I allude to the 

 Ailurus, which is remarkable in its group for the possession of re- 

 tractile claws. It might be asked, " Does this latter animal then 

 evince any affinity with the Cats, which are pre-eminently distin- 

 guished for their retractile claws ?" In no one other character can 

 I perceive the slightest approach ; and yet many zoologists in- 

 sist much upon the modifications of the extremities as of primary 

 importance in classification. There are undoubtedly cases in 

 which such characters are of considerable value, but this is 

 when they are combined with others of acknowledged value, as 

 in the case of the hoofed foot of the Ruminants, which is com- 

 bined with the ruminant stomach and other peculiarities. I 

 wish not to be misunderstood : I would reject no character, but 

 I do not regard the same modification as always of the same va- 

 lue ; that I should estimate by its constancy, combined with other 

 peculiarities. 



In the circle Qiiadrumana, I have placed the Galeopithecus or 

 Flying Lemur near the Cheiropterous group t ; not only be- 



* Mydaus, as well as Arctonyx and Ratelns, I do not hesitate to arrange 

 with the Badgers (Meles and Taxidea), which form, according to my views, 

 a little group of the MustelidcE (and may be called Mel'ma), and not of the 

 UrsidcB, witli which they are generally associated. They are clearly linked 

 with the t3pical Mtistelidce by means of the Skunks {MephUis). From the 

 UrsidfE, among other characters, they are readily distinguished by their pos- 

 sessing but one true molar on each side of each jaw- the Bear tribe having 

 two. The Mustelidce approach the Ursidce and the Insectivora in having no 

 ceecum, and in the absence of any decided division between the large and 

 small intestines. 



t The Galeoplfheci are arranged by many mammalogists with the Cheiro- 

 ptera; I have always however regarded them (as well as the Aye- Aye) as con- 

 stituting an aberrant form of the LenmridcB, and in addition to the points of 

 resemblance noticed in my paper on the group, published in the Zoological 

 Society's Transactions, I may call attention to others existing in the intes- 

 tinal canal, pointed out by Cuvier in his ' Lecons d'Anatomie Comparee:' 

 " Les Gali'opitheques se distinguent des autres Cheiropfcres, et se rappro- 

 chent des Lcmuriens par la presence d'un tres grand csecum, et la division du 

 canal intestinal en gros et petit intestin." — M. de Blainville, in his great work 

 on Osteology, now in course of publication, has placed the group in question 

 with the LemuridcE, and shown ample reasons for so doing. 



