ANATOMICAL NOTES ON MALAY APES. 8 1 



the lumbar region, ought to show variations. This position fur- 

 ther leads to a change in the mode of respiration, and we ouo-ht 

 again to find variations in the bony structure of the chest, as 

 in the sternum cartilages and ribs. And those parts are the 

 most variable in the monkey organism. 



(a) — Variations of the Sternum. (Breast-bone). 



In the cartilaginous foetal sternum, centres of ossification 

 appear, and it is the almost universal condition in the mam- 

 malian kingdom, for the first centre to spread and form the first 

 piece or manubrium, while the second, third, fourth and fifth 

 may or may not unite to form the sternum. But in the genus 

 Hylobates (gibbons) the rule seems to be for the first and 

 second pieces to unite and form the manubrium. Of the four 

 specimens I dissected, two united in this manner (diag. IV), 

 nd two did not (diag. III). Professor DwiGHT called attention 

 to this point (Journal of Anatomy, 1890) and gave the follow- 

 ing cases, which I tabulate: — 



Specimens in which the 1st • • 1 • n 



r 1 j • •+. j . specimens m whicn the 1st 



and 2nd pieces united to K , . ,. , . 



c r 1 • and 2nd pieces did not unite 

 form manubrium. r UU1LC ' 



Hylobates leuciscus, 2 speci- Hylobates Iar, 1 specimen, 



mens, (Dwight). (Dwight). 



Hylobates varie, 2 Specimens, 



(Knox). Hylobates lar, 2 specimens. 



Hylobates syndactylus, 1 Spe- | 



cimen. 

 Hylobates lar, 2 specimens. 



Total, 7 specimens, j Total, 3 specimens. 



Professor DwiGHT givesdiag. I shewing the same condition 

 in man, and diag. II shows it in Hylobates leuciscus. I found 

 a very close approximation to the same form in a specimen of 

 Semnopithecus albocinereus (see diag. VI). Professor DwiGHT 

 is of the opinion that it means nothing more than that nature is 

 on one of her accidental excursions, but the condition seems 

 rather too wide spread for that. The sternum in the quadru- 



