BIOLOGY. (II, B, i, d — h: ii, a — e; iii, a — c.) Echin. 41 
forked tubes (p. 7), supposed ova in hydrospirc folds (p. 20) ; 
Hambach (126). 
ii. Variation : — 
a. In form : — length and breadth of Holothnria atra; PearscJn (250) 
p. 203 . — Echinus acutus , high and low folms ; Simpson (294) p. 42. — 
Form and measurements of Scutella striatula ; Fallot (81) p. 74. 
b. In form and surface characters : — Numerous details of varia- 
tion in proportions, spinulation, etc. of Ecliinoderms of Spitzbergen 
district (vide iii, a, v) ; Michailovskij (223). — In shape and ambu- 
lacra of Scutella subrotunda ; Fallot (81) p. 81. — In contour, 
position of apex, arrangement of apical plates, and shape of anterior 
groove in Hemiaster cubicus; Fourtau (88). — In spines,, granules, 
scales, mouth-papillae, etc., in spp. of Asterias, Cribrella , Rhegaster , 
Solaster, Hymenaster , Pentagonaster , Ophioglypha, Ophiacantha ; 
Mortensen (227). — In shape of disc and in ratio R : r in Ophiocoma 
nigra ; McIntosh (212). — Ornament of Megistocr . ; Rowley in 
Greene (116) p. 131. 
c. In colour : — Colour in life of several spp. of Hoi. genera listed 
under iii, a, ii ; Perrier (254) : of spp. of Synapta, Cucumaria , 
Colochirus^ A ctinopyga (much variation in A . mauritiana), Stichopus , 
also in spirit of other spp. (see list of genn. iii, a, iii) ; Pearson 
( 250) : of numerous spp. of Ech. as indexed in iv, c, coloured figg. 
from specimens in spirit of spp. of Cidaris , Echinus, Strongylo- 
centrotus, Parechinus, Calveria (pis. i-iii) ; Mortensen (229). — In 
life and in spirit of Ast. dredged by S.Y. Belgica, see list under 
iii, a, v; Ludwig (204). 
In shape and size of coloured patch on disc of Ophiocoma nigra ; 
McIntosh (212). — In colour of spp. of Ophiocten , Ophiopholis , and 
’ Gorgonocephalus ; Michailovskij (223) pp. 492, 494, 498. — Ophio- 
coma niqra, black from Orkneys, red from Kincardineshire ; Simpson 
( 294) p/ 41. 
d. Meristic variation : — 
1. Variation from pentamerous symmetry : — in Ech. generally ; 
Hamann (125) p. 1302. — In number of rays in Stichastcr (p. 477), 
Crossaster (p. 484) ; Michailovskij (223 ). — Solaster papposus, 
10-18 rays; Simpson (294) p. 40. — 4 and 6 rays in Ophio- 
coma nigra ; McIntosh (212). — 4-rayed Dolatocr . ; Rowley in 
Greene (114) p. 102, & (119) pp. 157, 464. — Various instances, 
more or less complete, in Pentremites ; Hambach (126) p. 3. 
3. Reduplication or absence of parts : — number and size of Polian 
vesicles, stone canals, and tentacular ampullae in Holothuria 
atra ; Pearson (250) p. 203. — From 2 to 5 madreporites in 
Ophiocoma nigra ; McIntosh (212). — Abnormal Dolatocr. ap- 
proaching Stercocr . ; Rowley in Greene (119) p. 158. — Doubled 
ambulacra in Pentremites (p. 121), a ray partly suppressed 
(pp. 125, 126); Rowley in Greene (115). 
e. Abnormalities: — Cucumaria, torsion of ambulacra; Pearson 
( 250) p. 191. —Abnormal Actinopyga, see ii, D, vii ; Bell (12). — In 
Ech. generally ; Hamann (125) p. 1303. — Closure of poriferous 
zones in one or more ambulacra of an Ecliinocorys is teratologic, 
but connected with tendency of all Atelostomata to formation of 
petals; Lambert (176) p. 24. — Intercalated plate in R. circlet of 
Pentremites (p. 120), an ambulacrum aborted (p. 121), ditto in 
Codaster (p. 128); Rowley in Greene (115). 
iii. Secondary Sexual Characters : — 
a. Differences of Form or Structure: — Vacant. 
b. Differences of Colour: — Vacant. 
c. Protection of Y oitng : — Nursery formed by radioles above apical 
