58 THE TERTIAKY FOSSIL ECHINOIDEA 



Or^er ECHINOIDEA EXOCYCLICA. 



Suborder GNATHOSTOMATA. 

 Family CLYPEASTBID^. 



Subfamily EUGLYPEASTBID^. 



Genus CLYPEASTER, Lamarck, 1801. 



1. Clypeaster depeessus, Soweriy*. Plate X, Figs. 5-9. 



Many specimens of this species are in the collection from Kachh, and also in the 

 Museum of the Geological Society, which contains the type. 



The alliance to Clypeaster scutiformis, Lamk., is of the closest ; and the scooping 

 out of the actinal surface of the test, noticed by A. Agassiz in that species, is evident. 



The specimens are of different sizes, and some are very young. There is a variety 

 which > is rather more elongate than the types (Plate X, Figs. 5 & 7), and which 

 renders it necessary to absorb Clypeaster profundus, d'Archiac and Haime. 



The usual shape of large forms is depressed, hollow actinally, pentagonal at the 

 margin, which is slightly tumid. Test suddenly raised at the inner third of the petals 

 to the apex and depressed around the distal ends of the petals. Petals unequal, the 

 antero-lateral being the narrowest ; all are slightly tumid. The costse carry small 

 miliaries, and sometimes one or more larger tubercles resembling those of the inter- 

 poriferous area. The anus is far back and submarginal. Great variation in shape and 

 in the size of the petals is noticed, and also in the outline of the test. 



Locality. Arenaceous series or Miocene : about a mile east of Goir, near Narainsir ; 

 river east of Sujapiir ; near the south bank of the river from Teyra ; Falora river, 

 near Babua Hill; Babua Hill. Survey-numbers C 166, C 024, C 043 a, C 043 Af, 

 C 156, C 153. 



Illustrations of the Species in Plate X. 



Fig. 5. Abactinal view of test : natural size. 



6. Costse and pores : magnified. 



7. Actinal view of a specimen : natural size. 



8. Diagram of section. 



9. Needle-pillars: magnified. 



2. Clypeaster Waageni, Duncan & Sladen. Plate XII, Fig. 13. 



The test is thin, very depressed, slightly swollen at the rosette, and slightly 

 depressed at the ends of the petals, is longer than broad, broadest posteriorly, a long 

 pentagon in shape, sharply rounded in front, faintly reenteringly curved at the sides 

 and on the median line posteriorly ; angles bluntly rounded. 



The petals are very slightly tumid, broad, long, and widely open ; the interpori- 

 * Grant, Geol. Trans. 2nd ser. vol. v. part 2, tab. 24, fig. 26. 



