Between the lateral margins of the dorsal plates and the den- 

 tate elevations of the ambulacral plates are large sub-trigonal 

 open spaces. 



The plates are punctured by very closely arranged minute 

 perforations. 



The specimen from which this description is taken has three 

 arms nearly perfect, with a small fragment of the body attached. 



PROTASTER STELLIFER (N. Sp.). PI. i, fig. 2. 



Disk of medium size, flat, circular, slightly flexible, distinct 

 from the rays on the dorsal side, and has on that side a quinque- 

 dentate, stellate, central elevation, which again has a central, stel- 

 late depression of about one-half the lateral extension of the 

 stellate elevation upon which it is impressed. The points of the 

 star-like figure are opposite the several rays and extend about 

 two-thirds across the disk. 



Surface finely granulose. Rays slender, almost imperceptibly 

 tapering in the upper half of their known length ; rounding on 

 the dorsal side, with two rpws of regular, quadrilateral, alternating 

 plates which can with difficulty be made out, and which have a 

 fine granulose surface resembling the surface of the disk; opposite 

 each transverse suture there is a corresponding linear depression 

 across the surface of the opposite plate on the other side of the 

 median suture, which at first sight gives the impression that the 

 ray is composed of opposite plates of only one-half the real 

 length. 



Ventral side with ten short, oral plates which are slightly 

 separated below, and meet at the discal surface, where they are 

 rounded. 



Ambulacral series long, regularly quadrilateral ; alternately 

 arranged. 



Adambulacrals indistinct in the only specimens found showing 

 the ventral surface. 



Marginal series slightly imbricating; spiniferous; spines rather 

 short. 



Three specimens have been obtained. 



