132 



DR. C. T. TORSYTH MAJOB ON THE 



[Teh. 19, 



figures. Of Monkeys I have only added those of GalhtJirix 

 (text-fig 46, p. 142) and Glirysotlirix (lext-fig. 29, below).^ It 

 has been stated that the bone is missing in the latter genus ; as 

 may be seen from the figure, it is a large bone, and as such has 

 been mentioned already by Kcistlin ^. 



Text-fig. 27. 



Text-fig. 28. 



Text-fig. 29. 



Text-fig. 27. Orbital region of Avahis laniger, young, nat. size. 



Text-fig. 28. The same oi Propithecus coquereli (Br. M. No. 91.1.22.1), about | 



nat. size. 

 Text-fig. 29. The same of Chrysothrix scmreus (Br. M, No. 932 c), about nat. size. 



(Lettering as in text-fig. 26.) 



II. The Laoktmal Bone. 



As one of the distinguishing features between Lemurs and 

 Monkeys is considered the position of the lacrymal fossa, viz., 

 on the facial part of the skull in Lemurs, inside the orbit in 

 Monkeys and Man. 



The only writer, to my knowledge, who has considered this 

 condition more closely is Gegenbaur ^ ; a summary of his views 

 is given in the following. 



In lower Mammals tlie lacrymal is one of the facial bones ; in 

 the Sauropsidse particularly it is for the larger part situated on 

 the surface of the skull. In Lemurs it has preserved this position 

 in such a manner that not even the canalis lacrymalis begins 

 within the orbit. The same remark applies to Insectivora and 

 Chiroptera. In Monkeys, the bone has been stated by older 

 anatomists (Kostlin, Stannius) to occupy the same position as in 

 Man, having retreated within the orbit. Gegenbaur, however, 

 points out that considerable variations occur amongst Monkeys. 

 Of Platyrhinse, three genera are taken in consideration : Ateles, 

 Mycetes, and Nyctipithecus. In the former two " the lacrymal 



^ "Chez les Saimiris, qui, seuls dans tout I'ordre des Primates, n'ont pas 

 ^osplamim, la place ne reste vide que par suite d'un defaut d'ossifieation." 

 Alfr. Grandidier, Hist, pbys., naturelle et politique de Madagascar ; vol. vi. 

 Hist. Nat. des Mammiferes, par MM. Alph. Milne-Edwards et Alfr. Grandidier, 

 Tome I. — Teste i. p. 16, footnote (1875). 



2 Op. cit. pp. 92, 93. 



^ C. Gegenbaur, " Ueber die Pars facialis des Lacrymale des Mensehen," 

 Morph. Jahrb. vii. pp. 173-176 (1882). 



