38 Echin. 
XIV. ECHINODERMA. 
(139) pp. 232-234.—Antique character of deep-sea Ech. ; Seeliger 
( 275) p. 47.—Inability to deposit calcareous stereom in deep-sea 
animals, e.g. Ech ., not due to absence of calcium carbonate; Shipley 
r279) p. 244. 
ii. Relations of Ecliinodernia :—to classes of Phylum Archicoelo- 
mata (see iv, a); Masterman (203) pp. 170-176.—Early stages in 
evolution of Echinoderms from Dipleurula , relations to Hemichorda , 
and relations of Ast. to Crin .; Masterman (202).—Relations of 
Echinoderm ancestor to primitive Coelentera; Bather (18) p. 25. 
iii. Phylogenies of smaller groups :—Elpidiidae polyphyletic, 
being derived from various genera and spp. of Holothuriinae , whose 
descendents have passed through the Synallactine stage (similarly 
polyphyletic) to adapt themselves to deep-sea conditions, thus, 
Bathyplotes , Paelopatides , Pseudostichopus, tiynaUactes, and Meseres 
are connected with Stichopus spp., v 7 hile Mesothuria comes from a sp. 
of Holotkuria; Sluiter (284) pp. 1-6 (see further iv, b).—P hylogeny 
of Hoi., Ludwigia a link between Gucumariidae and Molpadidae ; 
Reiffen (258), p. 617. 
Further confirmation of evolution of Micraster , as in Row t e (202) 
Zool Rec. 1899, (pp. 9, 16, 46, 47, 48, 52); similar principles hold good 
for Echinocorys (p. 52): Rowe (265).-—Evolution of Turonian and 
Senonian spp. of Holaster and Micraster , chiefly in regard to apical 
system ; Elbert (103) pp. 128-140 and figg.-—Origin of Cidaridae, 
Lambert’s views criticised ; Tornquist (305). 
(B.) MORPHOLOGY. 
i. Anatomy 
a. EG HI NODERMA. 
1. General accounts :—popular; British Museum (45): Herd- 
man (149) pp. 55-58, fig. 7, 8: with special reference to struc¬ 
ture and habits of litoral forms on East coast of Scotland; 
Newbigin (221). 
The text-book definition criticised ; morphology discussed, 
Calycinal and Pentactaea theories rejected, Pelmatozoic theory 
restated and advocated; Bather (18). 
2. Symmetries :—Vacant. 
3. Homologies of Classes :—Russo’s observations as to origin of 
gonads, parietal canal, and water-vascular system in Antedon 
(see 292 Zool. Rec. 1900) upset the views of Jaekel as to the 
supposed parietal pore in Cystidea (130 Zool. Rec. 1899), which 
latter are based on observations of Seeliger on Antedon and 
Mortensen on Cucumaria , now contradicted by Russo; Russo 
(269). 
A Skeletal tissue or Stereom:—General account of its his¬ 
tology ; Dallinger (80). — Gives calcite reaction; Meigen 
( 208).—Of Echinus , Ophiura, Asterias , and Antedon , description 
of physical characters of the calcite ; Kelly (168) p. 469. 
5. Skeletal Anatomy:—Vacant. 
6. Hydrocoel and associated cavities:—Vacant. 
7. Coelom and other Body-cavities, and their Contents:— 
Summary of relations of lacunar and perihaemal systems; 
Cuenot (78) p. 235. 
8. Digestive System, Cuvierian organs :—Vacant. 
9. Nervous Systems and sense-organs:—Vacant. 
10. Mesodermal tissues (exc. skeletal) :—Origin of mesoderm 
