28 ECHTNOBERMA. 



Echini, Eichwald, Zool. Spec. (1829) i. p. 228. 

 Cirri-Spinigrada, Forbes, Brit. Starf. (1841) p. xv. 

 Adelostella (pars), Austin, Ann. 8f Mag. x. (1842) p. 111. 

 Echinodea, Dub. 8f 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, aetinogonidial, eleutherozoic, desm- 

 actinic Echinoderms in which the calycinal area may he very 

 extensively reduced or greatly metamorphosed ; the gonads are 

 unpaired and interradial ; the hody 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. EUECHINOIDEA. 



Euechinoidea, Bronn, Klass. u. Ordn. ii. Actinozoa (1861), p. 350 ; 



Zittel, Hdbuch. Paldont. (1879) p. 487 ; Duncan, J. Linn. Soc. 



xxiii. (1889) p. 4. 

 Autechinida, Haeckel, Gen. Morph. (1866) p. lxxii. 



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 1. REGULARIA. 



Regularia, LatreUle, Fam. Nat. (1825) p. 532. 



Les Cidarites, Ag. Mem. Soc. Neuch. i. (1836) p. 188. 



Echinides normaux ou reguliers, Gras, Ours. foss. de I'Isere, (1848) 



p. 20. 

 Cidarides, Desor, Syn. Ech. foss. (1858) p. 5. 

 Endocyclica, Wright, Brit. Foss. Echin. Oolit. i. (1857) p. 17. 

 Desmosticha, Haeckel, Gen. Morph. (1866) p. lxxii. 

 Regulares, Zittel, Hdbuch. Paldont. (1879) p. 487. 



Euechinoidea 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. 



