244 Annals of the South African Museum. 



short, well-spaced, rough spinules; a few of these are enlarged here 

 and there into short, thick spinelets and rarely a little group make 

 up a pedicellaria of a rudimentary sort. 



Adambulacrals about 37 on each side of the furrow; except the 

 first two or three and the distalmost half dozen, they are longer 

 than wide ; furrow-margin of each plate with about 8 conspicuous 

 spinelets, the middle ones 1'5 mm. long, the ad oral one shortest; 

 outside this series, on the actinal surface of the plate, near its 

 distal margin, is a single large spinelet, nearly equal to those on 

 the marginal plates; the rest of the surface of each adambulacral 

 plate is sparsely covered by spinelets like those on the actinal inter- 

 mediate plates. Oral plates rather large, swollen; each bears a 

 marginal series of a dozen spinelets, of which the first (inner) two 

 are the largest (about 2 mm. long), the others being gradually 

 smaller; surface of plate rather thickly covered with spinelets, of 

 which those near the interradial margin are largest, particularly 

 those at inner end of plate. Color, dull brownish-yellow, in the 

 present condition, dried from alcohol. 



Cutting through and laying back the skin of one ray reveals large 

 double ampullae, the complete absence of dorsal muscle bands, and the 

 genital glands confined to the interradial regions. Seen from within 

 the plates of the dorsal skeleton are circular and isolated, but 

 seemingly more crowded along the sides of the ray. 



P.F. 16743. Cape Point, N.E. by E. ^ E., 38 miles. 755 fms. 

 Gr. m. 1 specimen; adult. 



P.F. 16902. Cape Point, N.E. by E. i/4 E -, 40 miles - 800-900 

 fms. Gr. m. 5 specimens; young. 



P.F. 16931. Same station. 1 specimen; adult. 



P.F. 16944. Same station. 4 specimens; young. 



P.F. 17351. Cape Point, N. 86 E., 43 miles. 900-1000 fms. 

 Grey m. 2 specimens; young. 



Holotype, South African Museum no. A 6427, P.F. 16931. 



This species is undoubtedly near to P. bifrons (Wyv. Th.) but it 

 is at once distinguished from that species by the absence of large 

 spinelets on the actinal interradial areas and the presence of a 

 second series of spines on both sets of marginal plates in the inter- 

 radii. Another very marked difference is that in very young bifrons, 

 the infero marginal spines are well developed while in much larger 

 specimens of proteus, they are lacking or just beginning to appear. 



The series before me affords opportunity for a very interesting 

 study of growth changes which are of more than ordinary interest 



