198 



THE VOYAGE OF H.M.S. CHALLENGER. 



Chorological Synopsis of the Sjiecies herein described. 



1. Astropecten brasiliensis, Miiller and Troschel. 



Astropeden brasiliensis, Miiller and Troschel, 1842, System der Asteriden, p. 68. 



Localities. — Off Bahia. Depth 7 to 20 fathoms. 



Off Fernando Noronha. Shallow water. 



Remarks. — The examples from Fernando Noronha, when compared with similar-sized 

 specimens from Bahia, have the supero-marginal plates comparatively narrower, and the 

 rays also are proportionally rather narrower. In the armature of the adambulacral plates 

 the spinelets on the actinal surface of the plates immediately behind the furrow series 

 have often the appearance of forming a triple series, in consequence of the prominence of 

 the small lateral spinelets which accompany the large spine. These specimens have a very 

 prominent and well-defined conical eminence in the central region of the disk. 



2. Astropecten brevispinus, Sladen (PL XXXIII. figs. 1 and 2 ; PL XXXVII. figs. 



1-3). 



Astropecten brevispinus, Sladen, 1883, Journ. Linn. Soc. Lond. (Zool.), vol. xvii. p. 249. 



Bays five. B = 32 mm. ; r = 10 mm. B > 3 r. Breadth of a ray at the base, about 

 11 mm. 



Bays tapering^regularly from the base to the tip, and terminating in a point. Inter- 

 brachial arcs sli<rhtlv rounded. 



1 The exact station and depth at which this form was dredged are not recorded. 



