542 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Form of Human Blood Corpuscles.* — H. E. Radasch finds that 

 the majority of the red blood-cells in the circulating blood both in 

 foetus and adult are bell- and not disk-shaped. Contact with the air 

 causes the bells to collapse and assume the disk form. 



Number of Chromosomes in Man.f — J. Duesberg notes that there 

 is considerable discrepancy of statement as to the number of chromo- 

 somes in man. The number has been given as 16, 18, 24, 32, and 

 so on. Duesberg finds clear evidence that in the spermatocytes the 

 number is 12, and therefore 24 in the spermatogonia and the somatic 

 cells. Thus the number in man is the same as in mouse, salamander, 

 snail, salmon, lily, hellebore, etc. 



Suprarenals and Sympathetic System in Protopterus.J — Ercole 

 Giacomini describes the suprarenal bodies in Protopterus. Their seg- 

 mental association with the intercostal arteries recalls a similar disposition 

 in lampreys. The presence of chromaffin tissue beside the cranial portions 

 of posterior cardinal veins recalls Teleosteans. In their relations with 

 the intercostal arteries, and with the sympathetic, and in their segmental 

 distribution, there is an approach to Elasmobranch conditions. The 

 sympathetic, usually said to be absent, is represented by two very delicate 

 trunks along the sides of the aorta and by distinct traces of ganglia. 



c. General. 



Mammary Glands and other Skin-Glands of Marsupials.§ — 

 H. Eggeling points out that the integumentary glands of Marsupials, 

 like those of Monotremes and higher mammals, fall into two great 

 groups : (a) the " vital-secretory," permanently canaliculate, merocrinal 

 glands: and (b) the " necrobiotic-secretory " (where the cells are de- 

 stroyed), temporarily canaliculate, holocrinal glands. The first group 

 includes, besides the various kinds of mucous glands and the so-called 

 sudorific glands, also the mammary glands ; the second group includes 

 the so-called sebaceous glands. The close connection between the 

 mammary glands and sudorific glands is corroborated. In the Mono- 

 tremes epithelial muscular fibres persist in the whole length of the 

 mammary glands ; in Marsupials these occur only at particular places ; 

 in the higher mammals they seem to have almost entirely disappeared. 

 In the teat-less Monotremes the external musculature of the glandular 

 tubules co-operates in expelling the secretion. In Marsupials the 

 secretion is liberated by the sucking of the young, but there are 

 epithelial muscular elements left to help. In this respect, as in many 

 others, the Marsupials occupy an intermediate position. 



Growth of the Bronchial Tree.|| — J. M. Flint describes this in the 

 pig, where there arise from the pulmonary primordium four sets of 

 branches, all of which, with one exception, originate from the stem 



* Anat. Anzeig., xxviii. (1906) pp. 600-4. 

 t Tom. cit., pp. 475-9 (3 figs.). 



J Atti Eend. R. Accad. Lincei Roma, xv. (1906) pp. 394-6. 



§ Semon's Porsch. in Austral, u. d. Malay Archipelago, iv. lief 4, pp. 299-332. 

 See also Zool. Zentralbl., xiii. (1906) pp. 269-70. 

 || Anat. Anzeig., xxviii. (1906) pp. 272-86. 



