402 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the trackeolar network is found, and where there is consequently the 

 most abundant supply of oxygen. 



c. General. 



Arboreal Adaptations.*— L. I. Dublin reviews these in Mammalia. 

 He distinguishes (1) partially arboreal — including the majority of the 

 carnivores, insectivores, and rodents and Dendrohyrax ; (2) strictly 

 arboreal, subdivided into (a) modified for running on branches — arboreal 

 marsupials and lemurs ; (b) modified for suspension from branches — 

 sloths and bats ; (c) modified for swinging by fore limbs, hind limbs on 

 the marsupial type — remaining arboreal primates. The special features 

 characteristic of each type are briefly described. 



Seventy New Malayan Mammals.f — Gerrit S. Miller, junior, reports 

 on four large collections of Malayan Mammals made by Dr. W. L. Abbott 

 — rich in slightly differentiated insular forms of rats and squirrels, and 

 including peculiar insular species of porcupine and flying lemur, a dwarf 

 siamang, a member of a new monkey genus, Simias, and so on. The 

 title of the paper, " Seventy new Malayan Mammals," indicates how far 

 we are from having exhausted even the mammalian fauna. 



Seventh and Eighth Sternal Ribs in Man.J — J. D. Lickley dis- 

 cusses the significance of the occasional presence of an eighth true rib in 

 man, and of variations in the mode of sternal attachment of the seventh. 

 He considers that the caudal end of the thorax is degenerating, as is 

 shown by the diminution in the number of ribs which unite with the 

 sternum in man and the higher primates as compared with the lower 

 monkeys. The eighth rib has undergone so much degeneration that it 

 rarely joins in the sternum, and falls short of the middle line. When 

 degeneration has been partly arrested, it reaches the middle line without 

 becoming incorporated in or joining with the sternum. A similar de- 

 generation is affecting the seventh rib, which may not join or be incor- 

 porated in the mesosternum, but meet its fellow of the opposite side. A 

 further change brings the seventh in a few cases into the same position 

 as the eighth normally occupies, viz. it fails to reach the middle line, and 

 terminates by a secondary connection with the sixth. 



Asymmetry of Skull in Toothed Whales.§ — 0. Abel finds that 

 this is greatest where the nostrils are most highly elevated upon the 

 head, e.g. Platanista and Xiphinae, whilst in forms with the nostrils 

 nearer the front there is either no deviation from bilateral symmetry 

 (Zeuglodon), or only a trifling one (Phocc&na). 



Ear of Toothed Whales. || — G. Boenninghaus has made an exhaustive 

 study of the ear and related structures in Phocmia and other Cetacea. 

 From the great similarity of the rudimentary external ear to that of 

 the seal he assumes that when functional it acted similarly. In the 



* Anier. Naturalist, xxxvii. (1903) pp. 731-6. 



f Smithsonian Miscell. Collections, xlv. (1903) pp. 1-73 (19 pis. and 1 fig.). 



j Anat. Aczeig., xxiv. (1904) pp. 326-32. 



§ SB. Akail. Wiss. Wien, cxi. (1902) pp. 510-26 (1 pi.). 



H Zool. Jahrb., xix. (1904) pp. 1S9-360 (2 pis.). 



