32 Echin. 
XIV. ECHINODERMA. 
[1904] 
Agelocystidae come Ast. & Oph., and from Cystoblastidae descend Ech.; 
Haller (111a) p. 112. — Ech. derived from Ast., and neither from 
Edrioasteroidea ; Spencer (264). — General relations of groups of Ech.; 
DouvillId (66) p. 72. — Anterior ambulacrum of Spatangoids, its 
gradual specialization (p. 217), Evolution of plastron in Spatangoids ; 
Agassiz (3). — Origin of Pourtalesidae ; De Meijere (57) p. 1 57. — 
Evolution of apical system in Schizaster , this and Linthia derived 
from Periaster ; Tornquist (268). 
(B.) MORPHOLOGY. 
i. Anatomy : — 
a. ECHINODERMA. 
1. General Accounts: — Mainly recent Echinoderms, with orig- 
inal diagr. Ast., Oph., Crin. arm-sections, pedicellariae, otocyst, 
Asterias dissect., Ech. section, &c. ; Haller (111a). — Anatomy 
of Echinoderm type (p. 1-19, pis. i-x) comparative (p. 417- 
427) ; Delage (54). 
2. Symmetries : — Plant-like appearance and geometric regularity 
of certain Echinoderms due to sedentary life ; Lang (149). 
3. Homologies of Classes: — Vacant. 
I. Skeletal tissue or Stereom: — Crystalline nature ; Dou- 
villjS (66) p. 71. 
5-8. Vacant. 
9. Nervous system and Sense-organs: — General account 
with examples from Ophiocoma , Echinus , and Holothuria ; 
Roy. Coll. Surgeons (237). 
10-12. Vacant. 
b. HOLOTHURIOIDEA. 
1. General Account ; Delage (54), p. 274-303, pis. xxxvi-xl. 
2-8. Vacant. 
9. Nervous System and Sense-organs See n, b, i, a, 9. 
10, 11. Vacant. 
12. Genital System : — Cords of germinal cells in Holothuria 
homologous with genital cord of Ast. and axial organ of Crin. ; 
Polara (220). 
c. ECIILNOIDEA. 
1. General Account ; Delage (54), p. 160-201, pis. xxvi-xxxv. 
2. Symmetries: — Shape of test in Cidaridae, orientation of 
pentagons ; Agassiz (3) p. 1 . — Hcmiaster not bilaterally sym- 
metrical ; Bather (18) p. 300. — Ditto Linthia ; Newton (196). 
3. Homologies: —Vacant. 
L Stereom : — Structure of radioles ; Combes (45). 
5. Skeletal Anatomy : — Chief modifications in relation to mode 
of life ; Douvill£ (66) p. 72. — Morphology of Pourtalesid test 
discussed ; de Meijere (57) p. 157-171. — Ditto (p. 121), 
anal snout Spatangoidea (p. 148), apical system, Salenidae 
(p. 35) ; Agassiz (3). — Ditto, Schizaster ; Tornquist (268).— 
Ambital plates lengthened in various Spatangoids, cf. Melonites ; 
Agassiz (3) p. 184. — Interambulacrals, splitting of, Astropyga 
and Chaetodiadema ; Mortensen (195) p. 25. — Plastron of 
Pilematechinus compared with that of 0 faster, Abatus, Cardi- 
aster, Stegaster, et al., amphisternal derived from meridosternal ; 
Agassiz (3) p. 163. — Sternum, Echinocorytidae and Spatan- 
goidea ; de Meijere (57) p. 153. — Heteronomy, Spatangoidea, 
Pourtalesidae, &c. ; op. cit. p. 161 : normal in Hemiaster, 
ancient in Linthia ; Bather (18) p. 298 : explanation of phe- 
nomenon ; Lambert in Review. — Ambulacra, types of struc- 
