BIOLOGY. (II, F, iv—viii.) 
Echin. 49 
that a single species passes successively through the stages charac¬ 
teristic of Ocnus, Cucumaria , and Semperia , the first and last being 
therefore synonyms of Cucumaria ; H^rouard (150) p. xliv.— 
Young Holothuria rathbuni ; Clark (66) p. 259. 
c. Echinoidea \—Changes in apical system of Acropeltis from speci¬ 
mens 1*5 mm. diam. to adult 13 mm. diam.; S£guin (277).—Brephic 
Astkenosoma hystrix , podia in single rows ; Clark (66) p. 253. 
Neanic Porocidaris incerta , all stages Sterechinus antarcticus ; 
Koehler (172) pp. 7, 8. 
d. Asteroidea :—Age-differences in Astropecten duplicatus and A. 
antillensis ; Clark (66) p. 236.—Habits of young Asterias (p. 213), 
rate of growth up to sexual maturity (p. 215); Mead (207). 
e. Ophiuroidea :—Brephic Ophiopyrgus australis ; Koehler (172) 
p. 24.—Meeting of lateral arm-scutes in median line varies with 
age in Ophioglypha robusta; Rankin (252) p. 177. 
f. Crinoidea :—Young of Uintacr. socialis , with detailed account of 
growth in the sp.; Springer (290) pp. 60-86. 
g. Edrioasteroidea :—Course of subvective grooves in neanic as com¬ 
pared with adult Agelacr. alleganius , A. biittsi, A. hamiltonensis ; 
Clarke (69) pp. 190, 195. 
viii. Developmental mechanics and Experimental Embry¬ 
ology :—Discussion of polarity in Ecli. ovum, with special reference 
to work of Driescli, based on experiments with Strongylocentrotus ; 
Boveri (41) (see further under iv).—Development of isolated blasto- 
meres of Echinus , Sphaerechinus , and Toxopneustes , comparison with 
regeneration in adult ; Morgan (211) p. 953, and (213) pp. 18, 228, 
et sqq.—Development of partial embryos of Sphaerechinus , propor¬ 
tional number of cells (pp. 419, 423), the same for Toxopneustes 
(p. 429); Morgan (212).—Effect of various ions in producing separa¬ 
tion of cleavage cells to form dwarf embryos, or fusion of ova to form 
giant embryos, in Arbacia ; Loeb (189) p. 445. 
Hybrid larvae,—general discussion with reference to regeneration ; 
Morgan (213) p. 68 .—Strongylocentrotus lividus £ x Holothuria tubu- 
losa 9 (p. 455), Sphaerechinus granularis £ x Holothuria tubulosa 9, 
with or without aeration (p. 457); Rawitz (256).—Possibility of 
crossing Echinoderms and Annelids; Loeb (189) p. 451.— Asterias x 
Arbacia as described by Morgan, development really parthenogenetic ; 
Mathews (206). 
The salts necessary for development of Ech. larvae, substitution of 
sulphate ion by sulphite, thiosulphate, ethylsulphate, selenate, tellu- 
rate, of chlorine by bromine and iodine, of potassium by sodium, 
lithium, rubidium, and caesium, of calcium by magnesium, strontium, 
barium ; development to any extent only possible when the substi¬ 
tuted ion is a close chemical ally, and even then it is obstructed ; 
species investigated were chiefly Sphaerechinus gramdaris and Echinus 
microtuber culatus ; Herbst (147).—Effects of ether and pressure on 
segmenting ova of Toxopneustes and Arbacia ; Wilson (323 & 327). 
Development of enucleated ova of Echinus microtubercidatus , and 
effect on ova of chemical constituents of sperm in Arbacia and Sphaer¬ 
echinus ; Winkler (328).—Experiments of Pieri (190) Zool. Rec. 
1899 and Winkler (358) Zool. Rec. 1900, on ‘ spermase 5 tested in 
Arbacia and Strongylocentrotus with negative results ; Gies (133).— 
Attempt to induce development of A rbacia ova by addition of enzymes 
to sea-water ; Loeb (189) p. 456. 
Artificial parthenogenesis:—in Asterias ; Loeb et al. (190).—“Eplie- 
bogenesis,” i.e. production of offspring without the female element, 
attempt to prove from unripe Holothuria tubulosa 9 x £ of same sp. 
and x £ of Strongylocentrotus lividus ; Rawitz (255).—Criticism of 
