190 



PHYLUM ECHINODERMATA. 



fms. Luidia ciliaris, E. N. Atl., to 87 fms., L. sarsii, E. N. Atl., to 374 

 fms. 



Fam. 4. Pentagonasteridae. Interbrachial region of disc well de- 

 veloped, so the body is pentagonal with more or less concave sides. Mar- 

 ginals well developed. All the plates, both dorsal and ventral, form a close 

 mosaic, and are granular or naked. Anus present, but often hidden by 

 paxilli. Pentagonaster Linck. (Fig. 117) ; Stephanaster Ayres ; Astrogonium 

 M. and T. ; Calliaster Gray ; Chitonaster Slad. ; Calliderma Gray ; 

 Iconaster Slad. ; Gnathaster Slad. ; Nymphaster Slad. ; Paragonaster 

 Slad. ; Mediaster Slad. ; Nectria Gray ; Stellaster Gray ; Ogmaster v. 

 Martens ; Leptogonaster Slad. ; Goniodiscus M. and T. ; Mimaster Slad. ; 



FIG. 138. Porania glaber Sladcn, abaetinal view (after Sladen). 



Anihenoides Perr. ; Ho plaster Perr. ; British species : Pentagonaster greeni, 

 Faeroe Channel, 440 fms. Mimaster tizardi, Faeroe Channel, 550 fms. 



Fam. 5. Antheneidae. With well developed marginals, which may 

 bear granules or tubercles. Actinal interradial areas large and covered 

 with pavement-like plates, which bear large valvate pedicellariae. Anus 

 distinct. Anthenea Gray ; Goniaster L. Ag. ; Hippasteria Gray. 



Fam. 6. Pentacerotidae. Dorsal marginals smaller than the ventral, 

 often more or less hidden. Actinal interradial areas with large pavement- 

 like plates which bear unequal sized granules. With small valvate pedi- 

 cellariae. Abactinal skeleton reticulate. Anus distinct. 



Pentaceros Linck, Nidorcllia Gray ; Amphiaster Verrill ; Pentaceropsis 



