1904.] NATURAL SCIENCES OF PHILADELPHIA. 153 



in the totality of tlieir organization — man and anthropoids resemble 

 the Catarrhine monkeys far more than lemurs. Had Cope, at the time 

 he described Anaptomorphus, been aware that the placenta of Tarsius, 

 a closely affiliated lemur, was discoid in form and highly complex in 

 structure rather than diff\ise and non-deciduous, as in other lemurs, 

 his view of the lemuroid descent of man would have been strengthened 

 l^y an argument of far more weight than one based upon the presence 

 of an oblique ridge on certain teeth and the number of sacral vertel^rse, 

 which vary even in different individuals of the same or closely allied 

 species. Apart from the number of the teeth being the same in Platyr- 

 rhines and lemurs, the lemuroid character of dentition of the former is 

 clearly manifested by the long narrow inferior incisors of the South 

 American Saki (Pithccea). 



Further, in all Platyrrhine monkeys, as in most lemurs, the base of 

 the petrosal bone is excavated by that part of the lateral cerebral venous 

 sinus terminating at the postglenoicl fossa. Similarly in both lemurs 

 and Platyrrhines the malar bone is perforated by that branch of the 

 facial nerve known to the classical anatomist as the "nervus sub- 

 cutaneus malse." Again, in many Platyrrhines — as, for example, in 

 Cebus, Ateles, Nyctipithecus — a small unossified vacuity is exhibited in 

 the bony plate separating the orbital from the temporal fossa, evidently 

 the relic of the space by which the two fossa freely communicate in 

 the lemurs. 



In all the South American monkeys the tympanic bone retains more 

 or less its primitive ring-like form, the cavity of the tympanum lying- 

 close to the external wall of the cranium, its inferior surface, together 

 with that of the anchylosed penotic bone, exhibiting a very swollen 

 appearance. In this respect the Platyrrhine monkeys agree with the 

 lemurs, in which the inferior surface of the tympanum presents a large 

 rounded bulla, and differ from all Old World monkeys, in none of which 

 an auditory bulla is ever present. The otosteals of the Platyrrhines 

 resemble those of lemurs more than those of Catarrhines, monkeys, 

 apes or man. 



It is an interesting fact, also, that while the macula lutea is present 

 in the eye of man, apes and Catarrhines, it has never been found, so 

 far as known to the writer, in any Platyrrhine or lemur. 



As reference has been made to the character of the vertebrae in man 

 and Nycticebidffi, it may be as well mentioned in this connection tliat 

 in the lemur Galago the posterior edges of the spinous processes of the 

 lumbar vertebra3 present a pair of processes which, projecting back- 

 ward, clasp the anterior edges of the succeeding spinous process, and 



