BIOLOGY, (it, E, iii, iv: F, i—vi.) Echin. 43 
Resistance and response of spermatozoa of Strongylocentrotus to 
variations of osmotic pressure; Galeotti (92) pp. 881, 898.—Structure 
of Ech. ovum inferred from development of isolated blastomeres; 
Driesch (72) p. 509.—Number of chromosomes in Stronyylocentrotus 
(p. 72), and general constitution of Ech. ovum nucleus; Boveri (29). 
Segmentation,—started by spermatozoon, not qua organised struc¬ 
ture of centrosome, but qua chemical substance combining with 
ooplasm to produce centrosome; Boveri (30). — Of Ech. ovum; 
Ziegler (306).—Of fertilised Ech. ova without participation of sperm- 
nucleus; Teichmann (276).—Blastula of Echinus microtuberculatus , 
beginning to invaginate; Rhumbler (237) p. 431, fig. 16. 
v. Larval Stages:— 
(a) In North Sea; Meek (199) pp. 30, 31.—In plankton of G. of Triest, 
1901; Steuer (268) pi. i. 
(c) Of Strongylocentrotus lividus and Sphaerechinus granularis fully 
descr.; Steinbruck (267) pp. 2-22, pis. i, ii.—Pluteus of Mellita , 
sphincter muscles compressing gut, two pore-canals; Grave (105).— 
Development of larva of Echinus ; MacBride (181).—Natural Par¬ 
thenogenesis in &sphaerechinus, Toxopneustes , and Arbacia , growth 
of larvae checked by lowering of temperature; Viguier (286).—See 
also end of n, f, viii; Ariola. 
(d) Of Cribrella , detailed description, novel disposition of coeloms, 
discussion of MacBride and Goto; Masterman (195) p. 382.—Of 
Asterias glacialis of Auricularia type, not Bipinnaria ; Delage (64) 
p. 215. 
vi. Organogeny:— 
a. E chino derma :— 
(1) Origins and ulterior development of sexual cells, genital cords 
and pores, perihaemal aboral sinus, haemal aboral lacuna, 
intestinal absorbent strands, parietal sinus, ampulla, axial 
sinus, ovoid gland, and chambered organ; Russo (245). 
(4) Laws of crystallisation determine only the physical structure 
of the stereom, but its arrangement is determined by that of 
the mesoderm cells; Biedermann (23) pp. 160-170; and 
Herouard (125). 
c. Ech inoidea :— (l) Brief account of organogeny in Echinus miliaris : 
amniotic cavity not closed; hydrocoel; origin of radial canals 
and primary podia, buccal cavity or epineural space, epineural 
canals, buccal membrane; from left posterior coelom originate 
peripharyngeal sinus, perihaemal system, peribuccal sinus; 
elements of lantern formed independently at early stage by 
calcigenous cells of mesenchyme, but teeth formed in pouches 
of ectoderm (cf. enamel); nerves arise from ectodermic disc: 
Theel (277). 
( 6) Rudimentary right hydrocoel, left hydrocoel, radial canals, epi¬ 
neural & perihaemal spaces in Echinus ; MacBride (181 & 182). 
(7) Development and segmentation of coelom in Echinus’, Mac¬ 
Bride (181 & 182). 
(5) Development of masticatory apparatus from outer perihaemal 
ring, which is formed by 5 diverticula from the hypogastric 
coelom (1. post, coelom); Grave (105).—Masticatory apparatus, 
mouth, and oesophagus in Echinus ; MacBride (181). 
(10) Blood-system in Echinus] MacBride (181). 
(11) “Ovoid gland,” which “is in reality a genital stolon,” in 
Echinus ; MacBride (181). 
