MAMMALIA. 



81 



jaw of a young Triconodon from the Purbeck Beds of Swanage Table-case 

 is believed to show a single tooth being replaced in the ^^^ 

 typical marsupial fashion (see p. 17). The unique collection 

 from the Purbeck Beds, made by Mr. S. H. Beckles, is 

 arranged in Table-case 14a, and comprises several jaws of 

 Triconodon (Fig. 74) and Simlacotlicrium (Fig. 75), besides 

 remains of other genera described by Owen in his " Mono- 

 graph of Mesozoic Mammals" (Palreont. Soc, 1871). With 

 these are some jaws from the Stonesfield Slate including the 

 original specimen of Phascolothrrium huclclandi (Fig. 76), 



Fifi. 7G. — Lower jaw and teeth of rhaHcolothcriiiDi bucklandi, from the 

 Stonesfield Slate of Oxfordshire ; outline-fig. nat. size. (Table-case 14a.) 



which was so much discussed by Cu^■ier, Agassiz, and others 

 early in the last centur}^ Drawings of the American 

 Mesozoic jaws are placed with this collection for reference 



(Fig. 77). 



SUD-CLASS III. — PkOTOTHERIA. 



Order XI.— MULTITUBERCULATA. 



In some of the jaws of Mesozoic mammals, and in a 

 few similar specimens from the base of the Eocene, both in 

 Europe and Xorth America, there are crushing teeth which 

 bear two or three rows of tubercles or are provided with 

 tul)ercles round the edge. Tlie otherwise unknown animals 

 ti) whicli these jaws belong are named Multitulierculata, and 

 I hey are supposed to be related to the ancestors of the 

 living egg-laying mammals (Monotremata) of the Australian 

 region, because the young Ornifhorhynclius has somewliat 

 similar raultitubercidate teeth (see Fig. 82, p. 85). 



G 



