AlJAMH, i'HYLOQKSY OF THE JAW ilL'HCLEH 135 



MVftCLEH OF THE DEPREHHOR OR DIOAMTRIC GROUP 

 (ISSERVATED BY VJI) 



DepressfjT mandibube. 



MVSCLEH OF THE ADDUfJTOR OR TEMPORAL GROUP 

 IJTSERVATEIt BY V^ 



Cap\ti^mo.n4{'j0..o.ru. — i:. *" ■ " .? this msi^r. 'jt mru^:\^, which is 



the r^rptiiian mii-Vile of the -^..- rntist have been well subdirided: 



thus there was probably a large temporalis or medins slip filling the large 

 tempoT^d ifjssai and a superficial or masseter slip arising along the zygo- 

 matic arch; both ontdde and inside, both mnscles being attached on the 

 large dentar}-. The large carnivorous jaws of this form indicate a corre- 

 frrx/ndingly powerful muscle which : ^iDed the iemponl foeea but 



aL=o must have been attached to th«; of the zygomatic arch. The 



attachment mit^ have been on the ascending process of the dentary, £or 

 *he iposteriar bones of the jaw are too smalL Watson (1912, p- 581) says : 



It Ls a remai^able fact Uiat in Cjnodents inereaai^ size of tlie dentarj- and 

 f the mAsticatorj mx^scles, wlucb in Cpttoffwrthws must be inserted on it, is 

 correlated with a reduction and wealKmn^ of titie bade part of the jaw, wMcii 

 alone articolates wiUi tbe slcnll : not onlj are tbe actual bones snail, but tbeir 

 attaciunent to tbe dentary Ls wealc: tber mer^ rest in tbe groore in tbat 

 bone and are often di^laced in tbe foe^ ^nOs. 



As the ascending process of tiie dentary ac- -'- '>-^^ "'- --^-^ 

 mandibnlaris must have been attached diiefl' 



(a) Capiti-mandibularig ^j.r "• 



-riere is a large fossa for the ma--. . 

 ::iatch the lar^ temporal mass. It 



/Iter side of the zygot. .U:r«>i 



^ibercle on tiie lower .bably 



n the depression on th *>n in 



ther reptfleS; this supernciai s^ le 



mass and be connected "~ *' " d 



«fore. the pull of th- ? 



against the squamosal and not so m 

 *he posterior part of the ja — ' 



rom the dentary in some r. 



n its new TnammaliaTi fun 

 (h) Capiii-itutndibrjJ ' 



"otdd fin tiie temporal : - - 



f the dentMT, 



