ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 707 



Results of Castration in Man.* — E. Pittard has studied thirty 

 men belonging to the Russian religious sect of Skoptzy, founded towards 

 the middle of the eighteenth century, in which partial or complete 

 castration is practised. 



It seems from the data (1) that the operation diminishes, or retards 

 the growth — both absolute and relative — -of the bust, the head, and the 

 cranium in its three principal dimensions ; and (2) that the operation 

 increases or accelerates the growth — both absolute and relative — of 

 stature, of the lower limb, of the upper limb, and probably of the ear. 



Heterotypic Maturation-Mitosis in Amphibia.f — Thomas H. Mont- 

 gomery, jun., has studied the spermatogenesis of Plethodon cinerens and 

 Desmognathus fuscus, and comes to the conclusion that the heterotypic 

 division really represents a reduction-division. The normal number of 

 chromosomes is twenty-four ; in the nuclei of the spermatocytes of the 

 first order there are only twelve, which are interpreted as bivalent, arising 

 by the end-to-end coalescence of two univalent chromosomes in a U- 

 shaped loop. The longitudinal splitting, which occurs in these loops, 

 corresponds to an equation-division in the second maturation-mitosis. 

 In the first spermatocyte-division these bivalent chromosomes are divided 

 into two univalent chromosomes, which represents a true reduction. 



Acceleration and Retardation of Metamorphosis in Amblystoma 

 tigrinum.J — J. H. Powers has made many observations and experi- 

 ments on the causes affecting metamorphoses in the tiger salamander, 

 which is famous for its extreme variability. His facts lead him to con- 

 clude that the acceleration or retardation of metamorphosis is little, if 

 at all, a question of enforced air-breathing, of gill development, of 

 oxygenated or unoxygenated water, of temperature or of light. He does 

 not deny that these important factors have their influence, but his ex- 

 periments show that nutrition is the fundamental factor. Extreme 

 acceleration results from starving, a sudden check to a rich food-supply 

 is the common cause of early metamorphosis, a moderate but constant 

 food-supply postpones the change. In general terms, the chief factors 

 influencing metamorphosis are always sudden shifts in metabolism, 

 usually, or at least most readily, induced by changes in the food- 

 supply. 



Hybrid Nature of Triton blasii.§ — W. Wolterstoff has made a 

 number of breeding experiments, which appear to prove that Triton 

 blasii must be regarded us a collective title for the various hybrid-forms 

 of Triton cristatus and Triton marmoratus. A detailed study of the 

 progeny of " Triton blasii " is promised in a forthcoming volume of 

 " Zoologica." 



Development of Lungs in Discoglossus pictus.|| — E. Goggio has 

 studied the early stages in the development of the lungs in this Am- 

 phibian. He has been led to conclude that the primordium is primarily 

 endodermic, that it is only due in part to a diverticulum of the enteric 



* Comptes Rendus. cxxxvi. (1903) pp. 1411-3. 



f Biol. Bull. iv. (1903) pp. 250-69 (8 figs.) See Zool. Centralbl. x. (1903) p. 616. 



% Amer. Naturalist, xxxvii. (1903) pp. 385-410. 



§ Biol. Ceutralbl., xxiii. (1903) pp. 726-8. 



|| Atti. Soc. Tosc. Sci. Nat., xix. (1903) pp. 239-67 (2 pis.). 



