250 



ECHINODERMATA— ASTEKOZOA 



PHYLUM IV 



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

 no fossil forms ; but a considerable number of species and fragments (Figs. 

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



Mctopaster parkinsoni (Forbes), 

 (after Forbes). 



Fig. 354. 



Lower Chalk ; Sussex. 



A, Ventral aspect. ' B, Viewed from one side 



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

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

 and Mitraster Sladen, while Leptaster de Loriol is found in Jurassic strata. 



Fig. 366. 



SpTiaerites scutatus Goldf. 

 Upper Jura; Sontheim, 

 Wiirtemberg. 



Fi(i. 35' 



A, Sphaerites tahulatus 

 Goldf. B, Sphaer. imnctahis 

 Goldf. Upper Jura; Streit- 

 berg, Franconia. 



Fig. 355. 



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

 Bavaria. V- B, 0. thorarifer (Gein.). Planer ; Plauen, Saxony. 

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



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

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

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

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



