94 FOSSIL ASTEROIDEA. 



ADDENDUM (to Phanerozonate Asteroids). 



Further investigation, as a result of the privilege of investigating the fine 

 collection of Chalk Asteroids in the possession of Dr. Blackmore, of Salisbury, has 

 enabled me to describe several new species belonging to genera which have been 

 dealt with in previous pages. Some of these species had been recognised but not 

 described by Dr. Blackmore, to whom I am indebted for very many valuable 

 suggestions. 



Family— PENTAG0NASTERIM1, Perrier, 1884. (See p. 3.) 

 Genus— NYMPHASTER, Sladen, 1885. (See p. 14.) 



5. Nymphaster rugosus, n. sp. PI. XXIX, figs. 7, 7 a. 



Specific Characters. — All marginalia covered with granular prominences, which 

 are closely crowded, and in no case arranged in a linear series. No spine-pits on 

 the marginalia. Margin of disc lunate. 



Material. — Two specimens are known of this species. They are preserved in 

 the British Museum (Nat. Hist.), and bear the registered numbers 57516 (pur- 

 chased of W. Griffiths) and 76002 (Capron Coll.). Both specimens are imperfect. 

 The first-named specimen is figured PI. XXIX, fig. 7, and is taken as the type. 



Description. — The two specimens show the disc to have been small. The minor 

 radius in the specimen 57516 measures about 11 mm. The arms are broken off 

 short in both specimens, and therefore it is not possible to give the major radius. 



There are about eight infero -marginalia in each interbrachial arc. These are 

 all approximately equal in size, being 27 mm. long and T8 mm. broad. In shape 

 they are oblong. 



The margin of the disc is lunate. It is this character and the character of the 

 granular prominences which distinguish the species from N. radiatus. 



Locality and Stratigraphical Position. — Lower Chalk, Dover and Folkestone. 



