98 



FOSSIL MAMMALU OF THE 



Rat-kangaroos would liardly, in that state of division, be fit for swallowing ; accordingly we 

 find a ])rovision of not less than sixteen square and l)road-crowned, ridged, and tuberculate 

 grinders, superadded to the trenchant teeth, in order to pound up the chopped roots and 

 grass, and to well blend those dry vegetable cuttings with abundant salivary secretion, in 

 order to prepare a bolus fit for deglutition aud subsequent digestion. 



Fig. 16. 



^ XIX. Objections to the Carnivoritv of Flagiaulax examined. 



Tiie procumbent pair of lower incisors in Poephaqa oppose the upper surface, not the 

 end of the tooth, to three pairs of upper incisors, of which the foremost is longest. By the 

 analogy of ThyJacoleo the suberect pointed pair of lower incisors in Plaf/iaulax would he 

 crossed by a correspondingly developed and deflected pair of laniarifonn incisors ; and, if 

 these were followed by others in the premaxillary bones, they would probably be rudimental 

 and limited, as in Thylacoleo, to a single pair. 



The functional incisors in both jaws would act as in Thylacoleo, the lower ones like a 

 pair of bayonets, cemented side by side, with the muscular forces of 

 Ijoth mandibular rami concentrated on the thrust. A like advantage 

 in lethal stabbing power is gained by the same " collateral arrange- 

 ment in the axis "^ of the perforating stroke, in many of the Ferines 

 (" Carnassiers '') of the Cuvierian system. It is interesting to note, 

 however, that these instances occur in the orders (' Insectivores, 

 Marmpiauv') which I have proposed to place, through cerebral 

 characters, on lower steps in the jMaimnalian series ; the lissen- 

 cephalous and lyencephalous conditions of brain seeming to me of 

 greater taxonomic value than the " possession of claws and of three 

 kinds of teeth."" With lower intelligence the power of the killing 

 teeth is heightened; and a like relation is not unfrequently exemplified. 

 Observation of the habits and actions of the lissencephalous Otter 

 {Fotamogale, Du Chaillu), with approximate or " collateral " laniaries 

 (fig. IG), shows them to be as efficient, to say the least, in the capture and slaughter of its 

 prey, as are the divai'icate laniaries in the gyrencephalous Otter [Lufra). The Hedgehog 



' Falconer, "On the disputed Affinity of the Mammalian Genus Playiatdax from the Pmbeck Beds," 

 in ' Quarterly Journal of the Geological Society,' vol. xviii (1802), p. 352 ; also, "Palseontological Memoirs," 

 vol. ii, p. 4.35. 



- " Les Carnassiers forment une reunion considt'rable et vari^e de quadrupedes onguicules, qui possedent 

 Ics trois sortes de dents." Cuvier, ' Regne Animal,' torn, i, ed. 1829, p. 1 10. lint see, OwEX, "On the Charac- 

 ters, Principles of Division, and Primary Groups of the Class iLf«w»;a/(a," in 'Proceedings of the Linnean 

 Society,' Feb., 1857 ; also, " Anatomy of Vertebrates," 8vo, vol. ii, p. 290. 



3 I am indebted for tlie drawing from which cut fig. 16 was taken to Prof. Allman, F.R.S., of the Uni- 

 versity of Edinburgli, where the unique skeleton of that rare genus is pre.-^erved. 



Front view of upper 

 and lower incisive 

 laniaries, Poiamogale 

 veloT ; twice nat. size.' 



