250 



ECHINODERMATA— ASTEROZOA 



PHYLÜM IV 



Gray, was monotypic when described, and as now limited probably contains 

 no fossil forms ; but a considerable iiumber of species and frägments (Figs. 

 347, 348, 353) from the Mesozoic have been referred to it. An allied genus, 



Fig. 354. 

 Lower Chalk ; Sussex. A, Ventral aspect. 



B, Viewed from one side 



Metofiaster parkinsoni (Forbes). 

 (after Forbes). 



Metopaster Sladen (Fig. 354), is represented by numerous species in the 

 Cretaceous rocks of England. Other Cpetaceous genera are Pycinaster Spencer, 

 and Mitraster Sladen, while Leptaster -de Loriol is f ound in Jurassic strata. 



Siihaerites scutatus Gold f. 

 Upper Jura ; Sontheim, 

 Würtemberg. 



A, Oreastef Jurassims (Zitt.). Upper Jura ; Bemfeld, near Ingolstadt, 

 Bavaria. ^f^. B, 0. thoracifer (Gein.). Pläner ; Plauen, Saxony. 

 Marginal plate. C, 0. primaevus (Zitt.). Upper Jura ; Streitberg. 



A, Sphaerites tahulatus 

 Goldf. B, Sphacr. punctatus 

 Goldf. Upper Jura; Streit- 

 berg, Franconia. 



Several Recent genera, such as Calliderma Gray ; Nymphaster Sladen ; 

 Comptonia Gray, have been thought to have Cretaceous representatives, and 

 there is little reasori to doubt that many Cretaceous Starfishes of this family 

 were congeneric, at least in a broad sense, with those of to-day. 



