28 ECHINODERMA. 
Kchini, Lichwald, Zool. Spec. (1829) i. p. 228. 
Cirri-Spinigrada, Forbes, Brit. Starf. (1841) p. xv. 
Adelostella (pars), Austin, Ann. § Mag. x. (1842) p. 111. 
Kchinodea, Diib. § Kor. Vet. Ak. Hdlg. 1844 (1846) p. 255. 
Echinoidea, Bronn, Klass. u. Ordn. ii. (1860) p. 295; Duncan, J. 
Linn. Soc. xxiii. (1889) p. 4. 
The Echinoidea are caliculate, actinogonidial, eleutherozoic, desm- 
actinic Echinoderms in which the calycinal area may be very 
extensively reduced or greatly metamorphosed; the gonads are 
unpaired and interradial; the body is perfectly rounded, more or 
less flattened or bilaterally symmetrical, and is more or less covered 
by spines which may be long, stout, and strong, or present every stage 
of reduction to such as are fine and silky. The calcareous deposit in 
the peristome takes the form of polygonal plates which are arranged 
in regular rows and perforated in the radial area for the passage of 
the podia. They are all proctuchous, but the anus is not always 
opposite the mouth. Respiration partly by gills and partly by 
podia, which may be specially modified. 
Order 1. EHUECHINOIDEA. 
Euechinoidea, Bronn, Klass. u. Ordn. ii. Actinozoa (1861), p. 350; 
Zittel, Hdbuch. Paliont. (1879) p. 487; Duncan, J. Linn. Soe. 
xxiii. (1889) p. 4. 
Autechinida, Haeckel, Gen. Morph. (1866) p. Ixxii. 
The Euechinoidea are Echinoidea in which the number of rows of 
coronal plates is always twenty, or, in other words, in which there 
are always five pairs of ambulacral (radial) and five of interambu- 
lacral plates. 
Suborder]. REGULARIA. 
Regularia, Latreille, Fam. Nat. (1825) p. 532. 
Les Cidarites, dg. Mém. Soc. Neuch. i. (1886) p. 188. 
er ees normaux ou reguliers, Gras, Ours. foss. de VIstre, (1848) 
) 
Gitlarides Desor, Syn. Ech. foss. (1858) p. 6. 
Endocyclica, Wright, Brit. Foss. Echin. Oolit. i. (1857) p. 17. 
Desmosticha, Haeckel, Gen. Morph. (1866) p. Ixxii. 
Regulares, Zittel, Hdbuch. Paliéont. (1879) p. 487. 
Kuechinoidea in which the anus is at the opposite pole of the 
more or less globular body to the mouth, and is surrounded by a 
regular series of five radial and five interradial plates. Lantern of 
Aristotle well developed. 
