254 MR. ST. GEORGE MIVART ON INDRIS DTADEMA. [Mar. \4, 



inch. 

 Length between vertical planes traversing the most 



anterior and most posterior points of orbital margin 0*46 



Length from orbital margin to posterior end of skull r66 



Extreme width between outer margins of orbits .... 1*81 



Extreme width behind posterior roots of zygomata. . 1*49 



Width between nearest points of orbits 0"6l 



Length of palate 1 '20 



Breadth of palate between first premolars 0'45 



Breadth of palate at its posterior end 0"63 



Length of nasals 0'65 



Breadth of nasals 0'34 



Length of lower alveolar margin from front of first 



premolar to behind last molar 1 • 15 



Length of symphysis 080 



Height of condyle above alveolar margin 0*43 



Height of coronoid process above alveolar margin . . 0*70 



Of the rest of the skeleton of /. diadema I am entirely ignorant ; 

 but I have no doubt that when examined it will show an agreement 

 with the skeletons of the two other species, similar to that which 

 exists between their crania and dentition. 



As I have before observed, I feel convinced that sufficient grounds 

 do not exist for the generic separation of the species now described, 

 the Woolly Lemur, and the Short-tailed Indri. The dental cha- 

 racters are all but identical ; and as regards the crania the main di- 

 stinctions are those of the size of the entire skull, the proportional 

 length of the muzzle, and the development of the orbit — characters 

 which ill other genera of Primates vary considerably amongst species 

 of the same genus, especially when such genus contains species of 

 very different dimensions. 



The tail is short indeed in I. brevicavdatus, as compared with the 

 same part in either of the two other species ; but length of tail varies 

 much in Macacus and Ci/nocephalus, especially if, as I believe should 

 be the case, 31. imms be included in the former genus. 



The posterior incisors in I. diadema are decidedly larger than the 

 anterior pair, while the reverse is the case in /. laniger ; but, as 

 before observed*, /. brevicaudatus appears to be subject to some 

 variation as to the relative size of the two pairs of upi)er incisors. 



The shortness of the upper canine in I. laniyer distinguishes it 

 (as far as my observations have gone, and judging from De Blain- 

 ville's figure) from the two other Indrisinee ; but Prof. Van der 

 Hoeven's figuref and that of Prof. Vrolik^I leave it doubtful whether 

 this is not merely a sexual peculiarity. 



In other points given in my former paper as characters distin- 

 guishing J. laniyer from I. brevicaudatus, we have seen that /. dia- 

 dema presents an intermediate condition ; and the characters offered 



* P. Z. S. 1866, note in p. 154. 



t Loc. cif. pi. 1. fig. 6. 



\ Todd's 'Cyclopaedia,' iv. p. 215. fig. 136. 



