CLASS I 



ECHINOIDEA 



279 



Suborder B. STIRODONTA Jackson. 



Teeth keeled. Epiphyses narroiv, not meeting in suture over the foramen 

 magnum. Amhulacral plates compound or largely simple. Coronal plates not 

 imbricate. Primordial interamlndacral plates resorhed or retained in the hasicoronal 

 roiv. Base of corona resorhed or not. Oculars all exsert or becoming insert in the 

 sequence I, V, or V, /, IV, II, III. Periproct with prominent suranal, or with 

 many small plates, or four, or five large plates only. Peristome ivith ten primordial 

 ambidacral, also non-ambulacral plates. Lantern erect. Primary tubercles 

 imperforate, or exceptionally perforate. Jurassic to Recent. 



Family 1. Saleniidae Desor. 



Ambidacral plates compound, or largely simple. Primordial interambulacral 

 plates resorbed. Base of corona resorbed. Oculars exsert or becoming insert in the 

 sequence I, V, IV, II, III. Periproct with a permanent large suranal, or more 

 large plates, with small anal plates. Primary tubercles imperforate, or perforate. 

 No spurs from pyramids supporting teeth dorsally. Jura to Recent. 



Peltastes Ag, (Fig. 391). Amb straight or slightly flexuous, with simple 



....^/' 



Fig. 391. 

 Pdtastes, apical system ; 



m, madreporite. ''^g^^^^ Fto qq.^ 



Salcnia scut'ujara Gray. Wliite Clialk ; Charente 

 (after Cotteau). .4, Lateral and dorsal aspects of 

 tests, ^l\. B, Apical system, enlarged. 



plates abactinally and with small primary tubercles near the poriferous 

 areas. lAmb broad, with large, imperforate primary tubercles, diminishing 

 in size toward the poles. The suranal plate is small, in contact with the 

 lateral genitals, but not touching the posterior one. Upper Jura and 

 Cretaceous. 



Salenia Gray (Fig. 392). Test small, globose, or depressed. Amb plates 

 compound or largely simple. The suranal plate is in contact with all the 

 genitals ; oculars all exsert or ocular I reaching the periproct, perforated at 

 the adoral edge. Cretaceous to Recent. 



Goniophorus Agassiz. Upper Greensand ; Europe. Heterosalenia 

 Cotteau. Cretaceous ; Europe. 



Acrosalenia Ag. (Fig^s. 3Q8, C ; 393). Test depressed. ^7?i5 plates simple 

 primaries near the apical system, compound near the ambitus and actinally. 

 I Amb tubercles large, perforate, and crenulate ; those of the Amb much smaller, 

 and in two vertical rows. Periproct large, bounded anteriorly by the suranal 

 plate, which is in contact with the four large anterior genitals, or more 



