BIOLOGY, ('ll, F, V — viii.) 
Echin. 47 
Mann (303). — Relations of protoplasm in mitosis of shakon sporm-ova 
of Strongylocentrotus , in cases where a monaster replaces the usual 
amphiaster; Boveri (24). — Fusion and changes in form of nuclei in 
pressed blastulae or ova of Echinus , with myelin formation on nuclear 
membrane ; Albrecht (5a) pp. 120-124, 127, pis. a-d. — Necessity for 
presence of vegetative plasma in development of isolated blastomeres 
of Ech. ; Driesch (70). — Gastrulation of separated blastomeres in 
Sphaerechinus, compared with previous results in Toxopneustes ; 
Morgan (226). — Development of ova of Echinus microtubcYculatus 
fused before fertilisation ; Driesch (70). — Artificial production of 
double larvae and monsters in Arbacia , also fusion of ova forming 
giant larvae, fusion aided by parasite (cf. II, d, viii, c) ; Janssens (156). 
Asymmetric formation of first cleavage groove induced by subacetate 
of lead in Strongylocentrotus ; Ziegler (337) p. 174, figg. 
Development of larvae of Sphaerechinus and Strongylocentrotus 
hindered by alcohol, l°/ 0 to 2 , 5°/ e , the more alcohol the greater the 
hindrance ; Ziegler (338). — Action of solutions of non -electrolytes 
isotonic with sea-water on sperm-ova of Asterias and Arbacia , nuclear 
division without cleavage ; Lillie (188). — Free hydroxylions not 
necessary in normal fertilisation, and not present in normal sea-water, 
which is not alkaline; Loeb (195). — Action of distilled water and of 
sugar solution isotonic with sea- water on Ech. ova; Loeb (196) p. 67. 
— Effect of mechanical shock on development of ova and sperm -ova of 
Arbacia : Mathews & Whitcher (216). — Gastrulation checked by 
radium rays in Strongylocentrotus ; Bohn (19). 
Hybrids : Echinus microtuberculatus 9 x Strongylocentrotus lividus 
d reared past the metamorphosis, but Strongylocentrotus 9 x Ech- 
inus d died in pluteus stage ; Doncaster (63). — Sphaerechinus 
granularis 9 * Strongylocentrotus lividus d , or x Echinus micro- 
tuberculatus d j also Arbacia. pustulosa 9 x S. granularis d > reared 
under various conditions to determine causes of dominance of various 
characters, especially skeletal, correlation between characters, and 
causes hindering crossing ; Doncaster (64). — Echinus d x Sphaer- 
echinus 9 and Strongylocentrotus d x Sphaerechinus 9 also x Ech- 
inus 9? the male element influences tne larva in form, skeleton, 
number and pigmentation and arrangement of chromatophores, 
number of primary mesenchyme cells, and size ; general discussion 
with special reference to the different conclusions of Driesch ; Boveri 
(23). — Similaf crossings, also Echinus d x Strongylocentrotus 9 , give 
results conflicting with those of Boveri (23) except as regards form 
of plutei and, in part, distribution of chromatophores ; Driesch (69). 
— Asterias glacialis 9 x Arbacia pustulosa d also Strongylocentrotus 
lividus 9 x Asterias d ; Schuecking (291). — Asterias glacialis 9 
x Sphaerechinus granularis d gave a single blastula, x Toxopneustes 
lividus d ditto ; Ophidiaster ophidianus 9 x Toxopneustes lividus d •> 
gave first cleavage only (pp. 21, 23, 99) ; plutei obtained from Sphaerech. 
granularis 9 x Toxopneustes lividus d , and Arbacia pustulosa d , 
also Arbacia 9 x Sphaerechinus d and Toxopneustes d , but not 
from Toxopneustes 9 (pp. 23,89) ; Viguier (313). — Strongylocentrotus 
purpuratus 9 x Asterias ochracea d i n certain solutions reach 
gastrula ; Loeb (192). — Strongylocentrotus purpuratus or S. francis- 
canus ova fertilised by sperm of Asterias ochracea and reach gastrula, 
when medium is alkaline, in which case they are not fertilised by 
sperm of their own species ; Loeb (194 & 193). — See also Boveri (22) 
ii, F, iv. 
Artificial Parthenogenesis : — Summary of work published in 1901 ; 
Delage (48). — Regarded as a remnant of former normal partheno- 
genesis ; Wedekind (319). — Comparison with natural parthenogenesis 
