OOGENESIS, SPERMATOGENESIS* ETC. Geil. Sub. 45 
Parthenogenetic segmentation of Mammalian ova : in follicles under- 
going atresia, ova may show directive spindle and a polar globule 
precociously, and an incipient irregular parthenogenetic segmentation ; 
Henneguy (227). 
Parthenogenetic ova of Artemia salina. — Directive spindle consists not of 
24-26 bipartite chromosomes, but of 84 tetrapartite elements in a round 
plate. Only one polar body may be formed, or a second division may 
occur, but without extrusion, the retained half behaving like a sperm- 
nucleus ; Brauer (60). 
History of the ova which produce the different forms of Phylloxera ; 
Lemoinr (312). 
Graafian follicle, origin and history of. — Ova and follicular epithelium 
arise directly from the germinial epithelium. Waldeyer’s Eiballen are 
first formed. From these arise (a) the Pfliiger-Valeutin tubules, (6) typical 
primordial follicles, (c) atypical primordial follicles, (<7) Eiballen-follihel 
and (e) tubular follicles from delimitation of parts of (a). No new 
Graafian follicles arise in adult human ovary. In degeneration the 
nucleus undergoes chromatolysis or atrophy ; the cell-substance exhibits 
fatty or perhaps albuminous degeneration ; or there may be various 
combinations of these ; Schottlaender (462). — Origin and history ; 
Nagel (368). — Metamorphoses of ; Hoelzl (247). 
b. Spermatozoon. 
Spermatozoa of Axolotl ; Fick (157) : of Echinoderms; Field (168). 
Spermatogenesis : Summary and Bibliography ; Hermann (238). — * 
In Mammals ; Moore (359). 
Spermatogenesis : in Branchipus ; Moore (358) : in Styelopsis grossu- 
laria ; Julin (275). — Spermatogenesis in Decapod Crustacea: cephalic cap 
of spermatozoon derived from atrophied or transformed nucleus ; head 
formed by the vesicle, or secondary nucleus ; radiate filaments derived 
from the cytoplasm. Particular discussion of the morphology of 
the spermatozoa, their adaptations to fertilisation, the differentiation of 
the nuclear elements ; Sabatier (444). — Of a Turbellarian : spermatozoa 
distinctly cellular in nature. What seems to be absence of cytoplasm 
from the head of a ripe spermatozoon is only apparent ; Repiachoff 
(416). — History of Chromosomes in spermatogenesis of Ascaris megalo- 
cephala ; Brauer (61). 
Spermatolisis of Vertebrates ; D’Anna (8). 
Remarkable processes observed in spermatozoa of Bytiscus marginalia. 
Strange union of spermatozoa in pairs, a temporary conjugation or 
“ dejugation,” which may result in molecular exchange of substance, 
perhaps affecting variability ; Auerbach (10). 
Reduction-divisions in the spermatogenesis of Salamandra maculosa ; 
vom Rath (411). 
