OOGENESIS, SPERMATOGENESIS,- ETC. Gen . Sub . 69 
Heidenhain’s views ; Boveri (61). — Fertilisation of non-nucleated 
fragments of Echinodorm eggs. Cleavage to 16-cell stage observed. Some 
pieces were apparently large enough to form minute larvce. The 
spermatozoa of Echinus penetrate with difficulty into non-nucleated 
ovum -fragments of Sphcerechinus , as into nucleated fragments or entire 
ova. The hybrid larvae of Sphcer echinus- Echinus and of Sphcerechinus- 
Strongylocentrotus are very variable in skeleton-forming. Among the 
former some of the pure Echinus- type turn up. Boveri's conclusions 
non-proven ; Morgan (479). — In Echinoderm ova ; Reinke (572). — 
In Echinoderms : when nucleus of spermatozoon with indistinguishable 
chromosomes and caryolymph has passed outer portion of ovum it 
increases in size ; caryolymph and chromosomes reappear. History of 
sperm-centrosome and mitosome ; Field (199). — In Cyclops : do both 
centrosomes come from the spermatozoon, or from the ovum, or have 
they a paternal and a maternal origin, or does their origin differ in 
different cases ? In Cyclops , neither polar bodies nor germinal vesicle 
show centrosomes, attraction-spheres, or rays. The spheres of the 
segmentation-nucleus are derived solely from those of the sperm-nucleus ; 
Ruckert (598). — In Nematodes, movements of the two nuclei before 
fertilisation seem to be due to streamings in the ovum ; Ziegler (770). — 
In Nemerteans ; Burger (88). — Fertilisation in Seps chalcides ; Todaro 
(693) : in Ophryotrocha pucrilis ; Korschelt (352) : in ova of Sphcere- 
chinus and Phallusia there is no egg-astrosphere nor egg-centrosome. 
Both are brought into the ovum by the spermatozoon, and give rise by 
division to all subsequent astrospheres and centrosomes. The nstrosphere 
and centrosorae are elaborated out of, or under tho influence of, the 
middle piece of the spermatozoon; Hill (308, 309): in Echinoderm ovum ; 
Wilson & Mathews (762) : in Macrobiotus macronyx ; Erlanger (185): 
in Isopod Crustaceans ; McMurricii (419) : in Amphioxus ; Van der 
Striciit (676), Sobotta (662) : in Chcetoplerus pergamentaceus ; Mead 
(435) : in mouse; Sobotta (663). 
Polyspermy ; Braus (69), Duval (167). — Polyspermy, resulting in 
abnormalities, seems frequent in Amphioxus ; Yan der Striciit (676). — ■ 
Polyspermy, resulting in abnormalities, in Ophryotrocha ; Korschelt 
(352). 
Independence of paternal and maternal nuclear substance in the early 
development of Cyclops ; Ruckert (600), Haecker (276).— Independ- 
ence of paternal and maternal chromatin ; Zoja (778). 
Hybridisation in Echinoderms; Boveri (62). 
7. Embryological. 
General Lectures ; Bergh (36). — Elements of embryology ; Pre- 
nant (534). — Aide-memoire of embryology ; Girard (248). — Proposal 
of a typical series of embryological figures for Vertebrata ; Keibel (335). 
Catalogue of the processes concerned in Ontogeny : i. In migratory 
protoplasmic bodies (mesenchyme). II. In elongated protoplasmic bodies 
