296 



ECHINODEEMATA— ECHINOZOA 



PHYLUM IV 



petaloitl parts conjugated, the outer ones usually the largest. Peripetalous 

 fasciole present. 



Subgenus Triiiylus Fhill. {Jbatus Tvuachel). Recent.' 



Faorina Gray. Eecent. Fericosmus Ag. Cretaceous and Tertiary. 

 Linthia Merian (Desoria Gray) (Fig. 419). Anterior Amb in a deep 

 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. 



Schisaster Ag. (Figs. 420, 421). Resembling Linthia, but the apical system 

 is posteriorly eccentric, and the Amb very diverse. 

 Tertiary and Recent. 



Prenaster Desor; Oniithaster and Corasfer Cotteau. 

 Eocene. 



Agassizia Val. ; Moira A. Ag. Tertiary and Recent. 

 Moiropsis A. Ag. Recent. 



Fig. 420. 



Scliizasler archiaci Cott. 

 Eoceue ; San Giovanni Ila- 

 rione, near Vioenza. 



Fig. 421. 



Schizaster fragilis Ag. Apical sys- 

 tem, greatly enlarged (after Loven). 



J Fig. 1 422. 



Micraster coranganius 

 (Lam.). Apical system. 



Section C. Prymnodesmia. Subanal fasciole present. 



Micrasfer Ag. (Figs. 422, 423). Test cordiform, tumid, rather depressed. 

 Anterior Amb apetaloid, in a shallow depression ; antero-lateral Amb sub- 

 petaloid dorsally, diverging ; postero-lateral shorter than the others, Avith 



Fig. 42.3. 

 Micraster eortestuMiiarius Goldf. WUiti- Clialk ; Minidon, near Paris. Natural size. 



