378 THE FOSSIL ECHINOIDEA 



than it really is. In some examples the interradial incurvature of the margin is only 

 slight, and the general outline is more oval than pentagonal, and these appear to be 

 smaller examples ; in others again the breadth is nearly equal to the length. The 

 height and development of the dome varies greatly in different specimens even of the 

 same size. Not unfrequently examples show some irregularity in the form of the out- 

 line ; one of these has been figured in Plate LVIII, but the test otherwise is perfectly 

 typical in character and is beautifully preserved. 



Bemarks. In many respects this species recalls C. profundus (d'Arch.), nobis ; but 

 is distinguished by the strongly incurved margins of the interradia, by the closed petals, 

 which have also poriferous zones of different form, by the less abruptly rising dome, 

 and by the subplane actinal surface, with the abruptly depressed subcentral concavity ; 

 the character of the tuberculation is also different. The present form is very nearly 

 allied to C. placunarms, Agass. (C. AwmiVg, Klein, pars), the living representative of 

 which occurs in the Indian Ocean. The fossil is, however, distinguished by the more 

 prominent anterior radius, by broader petals which are less fully rounded at the extre- 

 mity, by the greater width and tumidity of the interporiferous area, and by the more 

 or less abrupt and conspicuous dome, as weU as the widely-spaced ornamentation. The 

 closed petals are very characteristic of C. suffarcinatus. It is distinguished from 

 C.latus, Herklots, from the Tertiaries of Java (which Michelin has united to C. placu- 

 narius), by the more elongate and inflated petals, the narrower poriferous zone, and the 

 apparently different margin of the test. Our form has also some alliances with the 

 living C. suhdepressm (Gray), Agass.; but the characters above noted wiU suffice to 

 distinguish it. It is, however, unquestionably more nearly related to the living than to 

 any of the fossil species. 



Locality. Kharak Island, Persian Gulf, near Bushire. Survey number G ^^^. 



Illustrations of the Species in Plate LVIII. 



Fig. 1. Abactinal view of the test: natural size. 



2. Actinal view of the test : natural size. 



3. Profile view of the test : natural size. 



4. Part of an ambulacral area and adjacent interradium : magnified. 



5. Part of the margin of the peristome : magnified. 



