408 Mr. F, M'Cay on some new Mesozoic Radiata. 



(Astero'ida^.) 



Goniaster [Goniodiscus) rectilineus (M'Coy). 



Sp, Char. Sides straight or nearly so ; on the dorsal surface each 

 side has eight finely granulated, moderately convex marginal 

 ossicles^ of which the two end or " ocular '' plates are tri- 

 angular and the four intermediate ones are quadrate, all of 

 one length, the width of each equal to half its length ; the os- 

 sicles of the oral side are similar except the triangular plate 

 at each end, which is there replaced by three smaller ones ; 

 plates of the disc small, polygonal and minutely granulated. 

 Width of each side 1 inch 3 lines ; length of marginal ossicles 

 3 lines. 



The straightness of the sides, and all the marginal ossicles 

 (except the eye-plates) being of one size, so that the inner and 

 outer boundaries of each row form two straight, parallel lines, 

 distinguish this species, which is, I think, only likely to be con- 

 founded with the G. regular-is (Park, sp.) ; I have good specimens 

 of this latter now before me, and it is distinguished from the 

 present species by having the margin of the sides convex out- 

 wardly, and the middle marginal plates being considerably the 

 largest, the others decreasing rapidly in size towards the angles, 

 so that the row of plates instead of being rectilinear and parallel- 

 sided is clearly elliptical : this character is represented in Park- 

 inson^s figure, but not to the extent to which it is seen in nature, 

 from the inner ends of the ossicles in his specimen being mani- 

 festly a little broken. 



Upper chalk of Norwich (two specimens). 



{Col. University of Cambridge.) 



Asterias {Astropecten) recta (M'Coy). 



Sp. Char. Rays five, straight, length from the base about three 

 times the width of the disc, widest at the base, tapering gra- 

 dually to the apex, with straight sides ; rows of lateral plates 

 averaging one-third the width of each ray (occupying rather 

 less at the base and rather more at the apex) ; they average 

 \^ line long and 3 lines wide, the long diameter or width di- 

 minishing gradually from the base to the apex ; angles be- 



* Prof. Forbes having recently published in the * Memoirs of the Geol. 

 Survey of Great Britain ' short descriptions of a number of new chalk star- 

 fishes, I trespassed on his good-nature so far as to send the notes and rough 

 sketches of mine for identification. The one above described is distinct from 

 any of his, but he suggests that the straightness of the sides may result from 

 the suppression of one of them : — the specimen I first sketched may have 

 been four-sided, for the two angles preserved are pretty nearly of 90°, but 

 the second specimen has portions of its five sides preserved, and has all the 

 above characters. 



