ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 543 



bronchus. There is an unpaired lateral evagination from the wall of 

 the trachea on the right side a short distance above the origin of the 

 two chief bronchi ; in certain other animals it is often present on both 

 sides. This evagination occurs early, during the formation of the 

 primitive lung-sacs, in embryos of about 8 mm. long. Subsequent 

 developments are discussed, and the methods of growth of the bronchial 

 tree, as described by various authors, are discussed and criticised. 



Experimental Pathology and Animal Classification.* — B. Galli- 

 Valerio discusses the significance of recent work, particularly the bearing 

 of the action of precipitins on zoological and botanical classification. 

 These reactions show a close relationship between Hominidse and 

 Simiidaa, less close between Houiinidae and Cercopithecidae. The anti- 

 serum of Cercopithecidas, however, gives a more marked precipitant 

 with the blood of' Hominidee and Simiidae than with that of Cebidae and 

 Hapalidas. The blood of lemurs is markedly distinct from that of all 

 Primates. 



The antiserum of pigs precipitates Cetacean blood ; that of Mammalia 

 generally does not precipitate with Monotremata, and similar tests mark 

 the Marsupials as a distinct group showing relationship with neither. 

 Analogous results with regard to other vertebrates are quoted, as well as 

 those of Decapods and Arachnids. An interesting case is that of 

 Limulus, whose antiserum precipitates the blood of Arachnids, but 

 which gives no reaction with that of Decapods. Most of the results 

 quoted in the paper are derived from the work of Nuttall. 



Skeleton of Musk Duck.f — W. P. Pycraft gives an account of the 

 peculiarities of the skeleton of this Australian diving bird, Biziura 

 lobata, noting specially the characters evolved in relation to its diving 

 habits. Of these may be quoted first the peculiar shape of the 

 lachrymal gland grooves. " There seem to be good grounds for 

 associating the development of this groove with the necessity for a large 

 supra-orbital gland in marine diving birds. This seems to be supported 

 by the fact that in the mergansers, which are fresh-water diving ducks, 

 this groove is wanting and the gland only feebly developed." A parallel 

 case is afforded by the grebes and divers. The former, which are fresh- 

 water divers, have much smaller supra-orbital glands than the latter, 

 which are marine. The occurrence of grebes and mergansers at sea 

 appears to be a recently acquired habit. Long hypapophyses with 

 horizontally expanded plates at the free ends of the spines, occur upon 

 the thoracic vertebras. " These have undoubtedly been developed to in- 

 crease the power of diving." The girdles, limbs, and ribs also show 

 special adaptive features. 



Organ of Jacobson in Sphenodon.J — R. Broom, from a study of 

 Sphenodon embryos, has been able to investigate the relations of this 

 organ, and to give a detailed account of the same. It is much less 

 developed than in lizards and snakes, and in structure comes nearer to 

 this organ in the Geckos than in the other lizards. In the way in 



* Bull. Soc. Vaudoise Sci. Nat., xlii. (1906) pp. 65-70. 



t Journ.Linn. Soc. (Zool.) xxix. (1906) pp. 396-407 (1 pi.). 



% Tom. cit., pp. 414-20 (2 pis.). 



