138 BULLETIISr 100, UXITED STATES NATIOI>TAL MUSEUM. 



as in Ctenoj)hor aster. This second comb is not found in T. craspe- 

 dotus. Proximally the first comb consists of about 5 larger spines, 

 the third from the upper the longest; and forming a continuous 

 series with these on the distal margin of the actinal surface are 3 or 4 

 smaller and more delicate ones. In front of them is a row of slightly 

 enlarged spinelets. Beyond the eight or ninth plate, only the lat- 

 eral comb remains and consists of 5 or 4 spines, and 3 or 4 at the 

 very tip. Owing to the tumidity of the outer end of the plate 2 or 

 3 of these spines are dorsal in position and are pressed against the 

 sloping side wall of the superomarginals. The second comb is con- 

 fined strictly to the first 4 or 5 plates, and to the outer end, forming 

 a parallel series between the base of the regular comb and the distal 

 edge of plate. There are 3 or 4 smaller spinides to the series; rudi- 

 ments of these spines persist to about the ninth plate. The spinelets 

 covering the surface of the plates are spaced and very delicate. On 

 the upper surface of the tumid outer end, near the first lateral spine 

 a tin}^ fasciculate pedicellaria often occurs. 



Terminal plate longer than wide, and ovoid in shape with a trun- 

 cate narrower end; proximal end with a slight notch next to paxillar 

 area, shallower than in craspedotus. 



Adambulacral plates proximally wider than long, gradually be- 

 coming narrower, until distally they are longer than wide. Furrow 

 spines 3, very long. The central one compressed, and almost trun- 

 cate. The laterals slender, slightly tapered and blunt. One or two 

 subambulacral spines stand on the margin owing to the very salient 

 furrow angle of the plate. These are usually bent away from the 

 3 furrow spines. On the surface of the plate are from 12 to 15 

 shorter, very slender spines, decreasing in length toward outer edge 

 of plate. These are variously arranged, sometimes in 2 longitudinal 

 series of 3 or 4 each, with 4 or 5 smaller spinules on the outer part 

 of the plate. The distal member of the first series stands on the 

 aboral facet of the angular margin; or 4 to 6 spines on the aboral 

 side of the plate form a fasciculate pedicellaria. This is composed 

 ■of 1 or 2 spines from each of 2 or 3 longitudinal series. On the outer 

 lialf of ray the pedicellaria is rare, and the spinules are in 2 series 

 with some irregular ones behind them, or in 3 series. The spines are 

 less numerous than in craspedotus^ and the pedicellariae are higher. 



Mouth plates relatively a little smaller than those of ci^aspedotus. 

 There are 2 large teeth to each pair of plates; all the other spines 

 are much slenderer and shorter. Furrow series angular as in cras- 

 pedotus^ composed of rather slender spines bent upward, and con- 

 tinued to outer end of plate along suture adjacent to first adambula- 

 cral in 8 to 10 smaller spaced spinelets. The series along the median 

 suture consists of about 10 to 12 slightly clavate spines and between 

 them and the marginal series is an irregular intermediate series of 



