246 ECHINODERMATA ECHINOIDEA SUB-BRANCH in 



Faorina, Gray. Recent. Pericosmus, Ag. Cretaceous and Tertiary. 



FIG. 



Hemiaster Orbignyanus, Desor. Upper Cretaceous ; Martigues,. Provence (after d'Orbigny). A-C, Ventral, 

 dorsal and side views of test, 1/1- A Pores of the odd Amb. E, Pores of the paired Amb, enlarged. 



Linthia, Merian (Desoria, Gray), (Fig. 397). Anterior Amb in a deep 



FIG. 397. 

 Linthia Heberti, Cotteau. Eocene ; Lonigo, near Vicenza. 8/4 natural size (after Dames). 



groove, the pores round and small, in pairs on either side. Antero-lateral 

 Amb longer and more divergent than the others, with 

 petals sunk in grooves. Pores conjugated. A peripetalous 

 and lateral fasciole present. Cretaceous to Recent. 



Schizaster, Ag. (Figs. 398, 399). Resembling Linthia, 

 but the apical system posteriorly eccentric, and the 



Amb very diverse. Tertiary 

 and Recent. 



Prenaster, Desor; Orni- 

 thaster, Coraster, Cotteau. 

 Eocene. 



Agassizia, Val. ; Moira, 

 A. Ag. Tertiary and Recent. 

 Moiropsis, A. Ag. Recent. 



FIG. 398. 



Schizaster Archiaci, Cott. 

 Eocene ; San Giovanni Ilari- 

 one, near Vicenza. 



FIG. 399. 



SECTION C. PRYMNODESMIA. 



Schizaster fragilis, Ag. Apical SubdUCtl fasciole present. 



system, greatly enlarged 

 Loven). 



Ap 

 (a 



Micraster, Ag. (Figs. 400, 

 401). Test cordiform, tumid, rather depressed. Anterior Amb apetaloid, in 

 a shallow depression ; antero- lateral Amb sub-petaloid dorsally, diverging ; 



