1910.] AXD THE MULTITUBERCULATA. 767 



independent group with no very near affinities with tlie Hving 

 Monotremes, Marsupials, oi- Eutherians. 



AV)0ut fifty years ago there was much discussion between Owen 

 and Falconer and others as to the habits of Plagiaalax, Owen 

 holding that it was a carnivore, the others that it was a vege- 

 tarian. Since then everyone who has expi'essed any opinion on 

 the subject has sided with Falconer ; and Gidley is also opposed 

 to Owen. He snys : — " The evidence that Ptilodus and PlcKjiaulax 

 were not carnivorous in habits seems rather conclusive, but as to 

 Avhether they were insectivorous, herbivq)ous, or frugivoi-ous 

 there may still be some differences of opinion. I am inclined to 

 consider them as frugivorous since the incisors were well fitted 

 for picking small fruits or berries, while the large cutting blades 

 of the lower pi'emolars were admirably adapted to cutting or 

 slicing the rinds of tough-skinned berries, or to chopping up 

 fleshy fruits held against the blunt-pointed premolars of the upper 

 jaw\ For masticating the seeds of such small fruits and berries 

 the multituberculate molars were amply sufficient." 



It has long seemed to me that as with Thylacoleo so with 

 Plaglmdux, Owen was right in regarding it as a carnivore. The 

 large size of the temporal fossse for the accommodation of powerful 

 temporal muscles, the small extent of the grinding surface, the 

 cutting mechanism of the anterior molars or premolai-s, and the 

 pointed condition and the mode of implanting of the incisors 

 together with their mode of passing between the vipper incisors, 

 all seem to me to favour a carnivorous habit. An insectivorous 

 habit, however, seems not improbable, and most small Carnivores 

 are also partly insectivorous. But a herbivorous habit for such 

 forms as Plagiaalax or Ptilodus seems to me very improbable, 

 and a frugivorous habit well-nigh impossible, Ptilodus from the 

 great disparity of its limbs must have been a ground-hopping 

 animal which was probably quite unable to climb trees. Even if 

 it could, fruits and berries are only ripe at one or two seasons of 

 the year, and an animal can only be a, satisfactoiy frugivorous 

 form if it can fly from place to place like the frugivorous bats or 

 birds. Further, typical frugivorous forms like Pterojms seem to 

 require neither powerful long incisors nor lai'ge cutting molars 

 or premolars. But the most serious objection to Plagiaulax being 

 a frugivoi^ous form is the fact that Plagiaulax lived in Jurassic 

 times, whereas what evidence there is, is against flowering plants 

 having been on the earth before Lower Cretaceous times. Conifers, 

 Cycads, and Gingkoes occurred before the Cretaceous, but, so far 

 as we know, no fruits or berries in the ordinary sense. 



It may be urged that the carnivorous mechanism of Plagiaulax 

 is of a difl'erent type from that of modern carnivorous mammals, 

 but there is this important point to bear in mind. Present-day 

 Carnivores almost exclusively feed on other mammals or liirds or 

 in some cases fish. But the carnivorous mammals of Mesozoie 

 times had to feed probal)ly almost exclusively on reptiles. With 

 the exception of Triti/lodon, which was probablv a root-eating 



50* 



