34 



PALEONTOLOGY 



and Arthraster are peculiar to the cretaceous ; and Ojphiv/m, 



Fig. 7. 

 Galeritidie; Asteriadw ; Crinoidea. 



i . Pygaster semisulcatus, Ph. ; Inf. Oolite, Cheltenham. 



2. Ananchytes ovatus, Lam. ; U. Chalk, Europe. 



3. Galerites albogalerus, Lam. ; U. Chalk, Kent. 



4. Scutella subrotunda ; Miocene, Malta. 



5. Lepidaster Grayi, Forbes ; U. Silurian, Dudley. 



6. Protaster Miltoni, Salter ; L. Ludlow rock, Salop. 



7. Comatula (Glenotremites), upper surface of body. 



8. Comatula (lower surface) ; Chalk, Sussex. 



9. Eugeniacrinus quinquedactylus, Schl. ; Oxjordiun, Wurtenibcrg. 

 10. Bourgucticrinus ellipticus, Mill.; Chalk, Kent. 



Astroyonium, Oreastcr, and Goniodiscus are both cretaceous and 

 living. 



Order 5. — EcuiNOlDEA. 



(Sea- Urchins.) 



Char. — Body spheroid or discoid, incased in a crust of in- 

 flexibly-joined calcareous plates, and armed with spines : 

 dental system complex, arranged so as to resemble a 

 " lantern." 



The Echinoidea appear first in the carboniferous limestone 

 ami attain their maximum in the cretaceous strata. In all 



