770 EXPERIMENT STATION RECORD. 



"The first maturation or reduction division in tlie hybrids is abnormal, in 

 that the chromosomes do not enter into the normal synapse to produce 8 synaptic 

 or bivalent chromosomes, but they are scattered as irregular chromatic masses 

 of unequal size on the mitotic spindle, and are irregularly distributed to the 

 opposite poles of the spindle. 



"The second maturation division in the hybrids is almost entirely suppressed, 

 the secondary spermatocytes proceeding without further division to form 

 spermatids and spermatozoa of twice the normal size. Many of these sperma- 

 tozoa are structurally normal, apart from their double size, while others are 

 abnormally twisted or beaded. All the spermatozoa were probably impotent, 

 since these hybrids and all others of a similar kind are invariably sterile. 



"The explanation of the sterility of such hybrids is found, in accordance 

 with Guyer's idea, to reside in the disturbance of the synaptic division during 

 maturation, this disturbance being due to the incapability of the chromosomes 

 derived froih the specifically different parents to fuse to form the normal 

 synapses." 



The male generative cycle in the hedgehog; with experiments on the 

 functional correlation between the essential and accessory sexual organs, 

 F. H. A. Marshall {Jour. Physiol., J^S {1912), No. 3-4, pp. 246-259).— Recent 

 studies of the sex glands of the hedgehog, combined with previous investigations 

 of other animals, led the author to the following conclusions : 



" The males of most, if not all, wild mammals experience a definite sexual 

 cycle, the testes and accessory generative organs passing through alternate 

 periods of rest and activity, but in the domesticated varieties and in man the 

 period of rest is liable to be much reduced or may be absent altogether. . . . 

 The vesiculse seminales are secretory glands, and do not contain spermatozoa 

 either in the breeding or in the noubreeding season. Complete castration during 

 the period of rest prevents the seasonal development of the vesiculse seminales 

 and other accessory male organs, or, if such development has already begun, 

 arrests its further progress. Unilateral castration, however, does not inhibit the 

 growth of the accessory organs and has no effect on the symmetrical arrange- 

 ment of these organs. Vasectomy, either unilateral or double, does not inhibit 

 the growth of the vesiculse seminales or other accessory organs, but unilateral 

 vasectomy may prevent the full development of the testis on the side of the 

 operation, as compared in size with the testis on the unoperated side. The 

 periodic development of the accessory organs is not due to stimuli set up by 

 sperm ejaculation, but is probably the result of an internal testicular secretion 

 elaborated in the interstitial tissue during the season o4 generative activity." 



The maturation divisions of the mammalian ovum, M. Athias {Arch. 

 R. Inst. Bact. Camara Pcstana, 3 {1912), No. 3, pp. 287-370, pis. 4).— A study 

 on the segmentation of the ovum in the cat, rat, mouse, and other small mam- 

 mals. A bibliography is appended. 



Development of new feathers, Frieda Bornstein {Arch. Naturgesch., 77 

 {1911), I, Sup. 4, pp. 1-11, pis. 2; ahs. in Jour. Roy. Micros. Soc. [London], 

 1912, No. 3, p. 299). — This is a study of the histology of the feather in young 

 ducks, pigeons, and other birds. 



"A new germ is always formed for a new feather ; the new germ arises while 

 the old feather is still growing; it is formed from the malpighian layer, at one 

 side of the base of the feather follicle. The new feather germ forms a process 

 which grows into the deeper layers of the cutis, and from this process the new 

 papilla is formed. The old papilla atrophies after the old feather falls off. 

 A study of the foot of the capercaillie, where feathers and scales occur in close 



