286 



ECHINODERMATA— ECHINOZOA 



PHYLUM IV 



re-entering angles. Petals long, broad, tumid ; pores wide apart, unequal, 

 conjugated. Periproct near or at the edge. Internal structure not forming 



a double wall covering the 

 Amb. This genus includes 

 some of the largest known 

 Echinoids. Eecent species 

 are littoral, or shallow- 

 water inhabitants. Tertiary 

 and Recent. 



Anomalanthus Bell. Re- 



>if^ Cent. Laganum Gray. Be- 



longs properly to a separate 



rj'l family or subfamily. Ter- 



'^*'' tiary and Recent. 



Family 2. Pibulariidae 

 Gray. 



Flu. 401. 



Clypeaster cbegypticus Mich. Pliocene ; Gizeh, near Cairo. Fragment 

 showing internal calcareous deposlts. au, Auricles. 



Test small, with rudi- 

 mmtary, widely open, few- 

 pored petals. Interambulacra 

 small, with a single apical and a single peristomal plate. Jmhulacra limited 

 adinally on the interior of the test hy low vertical partitions at their sides, radiating 



Fig. 402. 

 c?' grandifiorus Bronn. Miocene ; Boutonnet, near Montpellier, i/o natural size (after Desor). 



toward the peristome. Perignathic processes broad, low, situated on each inter- 

 ambulacrum. Periproct usually actinal. Cretaceous to Recent. 



Echinocyamus Leske (Fig. 403). Test thick, depressed, pyriform or sub- 

 circular in outline, concave actinally. Amb broader than the lAmb, short 



