PALASTERTNA. 



221 



earlier observers, who had not noted the oral position of the madreporite, classified 

 the form, in consequence, among the Fhanerozonate Asteroidea. The apical 



Text-fig. 157. — Plan of ossicles on the apical surface of Palasterina primseva. I.R., primary interradial; 

 Ir., intermarginalia ; R., radial ; S.M., supero-marginal. x 5. 



plates are covered with pustules, which are shown slightly exaggerated in 

 Text-fig. 158. 



S.M. 



(&) 



(a) 



R'. 



Text-fig. 158.— (a) Wash-drawing of ossicles across the apical surface of a somewhat compressed specimen 

 of Palastenna primseva. I„.M., infero-marginal ; R., radial ; S.M., supero-marginal. x 30. (6) On left an 

 isolated ossicle with detached spine from a specimen of P. antiqua (Brit. Mus. no. 40301). 



The faint ornament suggests that the spines fitting on these pustules were slender 

 and easily destroyed, and they are usually missing in the specimens. If present 

 there is only one to a plate (Text-fig. 158 &), and one may surmise that this was 



30 



