Gregory: notharcti's, an American eocene primate 



73 



strongly pronated forearms. 80 too, the head of the radius in ]n-imates l^ecomes circular, so 

 that it can the more easily rotate within the orbicular ligament, antl it is the head of the radius 

 which articulates with the groove that now separates the outer lip of the trochlea from the 

 ball-like capiteUum.^ (Plate XXVII.) 

 All these considerations are in harmony \\\{\\ other evidence to the effect that in Nofharcfm the 

 forearm was habitually partly supinated, as a part of the limb-grasping series of adaptations. 



Special resemblances l)etween the humeri of N^olhardus and a certain humerus referred to Adapis 

 nwrinus: by Filhol ai'e as follows (Figs. 6, 7): 



(1 ) In 1).)th types the supinator crest extends much further up the shaft than it does in niod(>rn lemurs. 



(2) The middle i)art of the shaft is less elongate than in most lemurs. 



(3) The entocondylar process extends fui'ther inward than in modern lemurs. 



(4) The capitellum is more ball-like and the outer lip of the trochlea less defined. 



(5) The tuberosity for the teres major is more conspicuous. 



But a certain humerus catalogued as "Adapis parisiensis" (Amer. Mus. No. 10018) has a straighter, 

 less flaring supinator crest, more like that of Projritliecus; and in the specimen of Ad(tpi.\ iiiaqiiiiH CI) figured 

 by Filhol the middle of the shaft is ap])roaching the cylindrical lemiu'iform type. Tluis these hum(M'i 

 referred to Adapis are a stage nearer to the lemuriform type than are those of N^olhardu.s. 



Among recent Lenmrida', Ijpih nnir has a hmnei'us (Fig. <S) wliicli is verA' like that of Nolliarrlvs in 

 many respects, but differs in the following: 



(1) The shaft as a whole is straighter. 



(2) The edge of the j^ectoral crest is curled o\'ei' and tlie crest projects more prominently at the 



lower end. 



(3) The head is an elongate oval. 



(4) The tuberosity for the teres majoi- is further up the shaft, nearer the prominent lesser tubei'osity. 



(5) The mid-shaft is longer and I'ounder in section. 



(()) The supinator crest flares less, is straight(M-, and does not extend so far up the shaft. 



(7) The trochlea is smaller, has a smaller innei' lip and a larger outer li]), this implying a greater degree 



of supination. 



(8) The entocondyle is directed slightly ui)ward instead of sti'aight inward. 



Characters (1), (2), (4), (5) and ((i) also hold good in Lemur ran'iis and L. iiiariqoz. In these, how- 

 ever, the head is larger, the trochlea has two neai'ly parallel lips and extends further around on the l)ack 

 of the shaft, the olecranal fossa being deep; this implies free supination and extension. The entocondyle 

 is shorter and thicker (Figs. 6, 7). 



Fif^-. (■). ( "oMip;n'ati\ e seri(^'s: hwmm o\ yfiihan tit.s, Aild pi Lcniiir. liack \ i('w. Natural size. 



1. Nolliairliis oshiinii. Aiiicr. AIiis. No. 1 1474. 



2. •■Aildiii.^ pans,, nsis/^ .\(\,;- ImIIioI, 



3. LciiHir ,„ui,f,,,:^ Ain.T. .Mils X,.. 2'2SS(i. 



Fiji'. 7. ( 'oinparati\-e .scries: liuini ri of XiiflidiTtii.s (1 ), Adaj.is (2, .'!), /.( //,///■ (4), Crhus Ci), Ilapnlr (O), Mucanis (7). 

 Front \icw. Natural size, except Nos. (i, 7. 



1. Xolharrliis oslionil. Ainer. Mus. No. 1 1474. x {. 5. Cehu^ hijpo'eucuf. Amer. Mus. No. 14016. X} . 



2. A<lai,is iinnsirnsis." After Filhol. X i. 6. Hapalciip. Amer. Mus. No. 17.574. x l 



3. "Athi/iix /ww,V7/.NV-x." .Vmer. Mus. No. 10018. X 7. Macarm ncmestritms. Amer. Mus. No. 14012. X f. 



4. LcNiur ninnno:. .Viiier. Mus. No. 22886. X '. 



' These (ipposite lines of speeiiilizatioii are wcW shown li)- eeini)ariug the distal eiul of the humerus fif a sloth with that of a dog. 

 '! Ill' fiiniier- indirates extreme supinaliun, the lallei- exti-eme prunalion. 



