42 Echin. 
XIV. ECHINODERMA. 
area in Hypsiechinus coronatus ; Mortensen (229) p. 89, pi. vii. 
Marsupial ambulacra of Epiaster nutrix\ Lambert (174) p. 87. 
Young on ventral surface of disc in Anasterias chirophora (p. 47) 
and A. belgicae (p. 53) connected with one another, but not with 
the mother, by a white strand ; general remarks on nursing Ast., all 
are cold-water forms, complete list of spp. (pp. 54-58); Ludwig 
(C.) PHYSIOLOGY. 
i. General : — Vacant. 
ii. Circulation: — in Hoi., see n, c, iv; Enriques (73).— Circulation 
of internal liquid due to rhythmic contraction of respiratory trees in 
Hoi . ; Henri (136). 
iii. Respiration : — Membranes surrounding internal fluid in Ech. are 
permeable to water but not to its contained salts, whence osmotic 
regulation of the fluid, proof from Strongylocentrotus lividus , Sphaer- 
eckinus granulans, and Spatangus purpureus ; Henri & Lalou (139): 
same is case with membranes of respiratory trees, polian vesicle, and 
digestive tube in Holothuria tubulosa and Stichopus regalis ; Henri & 
Lalou (140) : thus they regulate osmosis of internal liquids to exterior ; 
Henri & Lalou (141). 
iv. Alimentation and Digestion :— Digestion, circulation, and ab- 
sorption in Hoi. esp. Holothuria tubulosa , and critical examination of 
results of Frenzel (1892), H^rouard (1889), Cu^not (1891), Schultz 
( 1895), et at; Enriques (73).— Digestive ferments in caecum of 
Spatangus ; Henri (135, 137, 138). 
v. Excretion and its Products: — Excretion by genital organs of 
Holothuria during their quiescent stage; Russo (277). — Poisonous 
secretions, toxalbumins and alkaloids, of ovaries, and to less extent of 
testes, in Toxopneustes lividus ; Loisel (198). 
Colour, see ii, b, ii, c. 
vi. Sensation: — So-called heliotropism of larvae discussed; Viguier 
( 313) pp. 65-69. 
Muscle-contraction and reflexes in Stichopus regalis ; Henri (130) : 
no wave propagated by longitudinal muscles ; Henri (131): but the 
stimulus is transmitted by the radial nerves, and the nerve-ring acts 
as central nervous system ; Henri (132) : action of strychnine, atro- 
pine, and nicotine, shows that radial nerves consist of a series of 
elementary nerve-centres, subordinate to the nerve-ring ; Henri 
( 133). — Rhythmic waves of contraction descend oesophagus and acces- 
sory intestine of Ech., causing flow of water ; Henri (134). 
vii. Miscellanea and Experimental Physiology : — Movements 
of Ech. gastrula, ciliary and muscular forces contrasted ; Bohn (20). 
Sphaeridia removed from Strongylocentrotus are not regenerated ; 
Delage (51). 
Chemical constitution, esp. position of phosphorus, in ova of 
Strongylocentrotus and Sphaerechinus ; Bertolo (13). — Resorption of 
unused gonads by phagocytes in Echinocardium ; Caullery & Sied- 
lecki (28). — Enzyme in gonads of Arbacia aequituberculata ; Robert 
( 168) pp. 128, 150, 181. 
(D.) BIONOMICS. 
i. General Accounts : — Semi-popular, of recent Echinoderms from 
bionomic stand-point ; Jordan & Heath (160) pp. 140-150. 
ii. Special habits : — Hibernation, in December Thyone withdraws 
