156 



OOLITIC OPHIURIDJE. 



The fact of its limitation to the upper portion of the Lower Oolites is another 

 illustration of a former remark that a great break appears to have taken place in the 

 forms of life which prevailed in the upper, when compared with those which existed in 

 the lower portion of the Inferior Oolitic series. 



Ophiurella nereida, Wrigld, n. sp. Woodcut figs. 39, 40. 



Disk small, irregularly pentalobed, each lobe consisting of a shield-like elevation 

 Fig. 39. Fig. 40. 



Ophiurella nereida, Wright. 



formed by the radial plates, which are covered by a tegumentary membrane closely 



