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BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



ridges, excepting in the outer part of the spine. The surface of the spine 

 is otherwise covered with sparse, low, bush-shaped hairs (fig. 20c). 

 The collar is about 3 mm. long, increasing very slightly in thickness 

 toward the very prominent milled ring. The apical primaries in 

 adult specimens are apparently much shorter than the ambital ones, 

 when fully formed. The oral primaries are very slender, smooth, and 

 straight; the fourth is transitional to the ambital spines. 



The secondary spines are very slender and pointed; the scrobicular 

 ones are about 7 mm. long, flattened, with a slight concavity on the 

 outer side in the basal part, made somewhat more conspicuous by a 

 dark-colored median stripe (pi. 80, fig. 7) ; the marginal ambulacral 

 spines are about 4 mm. long, almost setaceous. The miliary spines 



are likewise compara- 

 tively long and slender 

 and are pointed. The 

 secondary spines, even 

 the scrobicular and mar- 

 ginal ambulacral spines, 

 are generally erect; but 

 this may probably, to 

 some degree at least, be 

 due to preservation. 



The large globiferous 

 p e d i c e 1 1 a r i a e which 

 were observed only on 

 the larger specimen from 

 station 5278 (the type 

 specimen) are of the 

 usual form, with a well- 

 developed limb on the 

 stalk (pi. 80, fig. 9). 

 The small globiferous pedicellariae are usually very long stalked, the 

 stalk being up to 5 mm. in length and rather thick; the head is up 

 to 1 mm. long; the valves are of the usual form, with a small, but 

 distinct, end tooth (pi. 80, fig. 8). Tridentate pedicellariae are 

 usually rather conspicuous, with the head upto 2.5 mm. long and 

 the stalk of a length similar to that of the small globiferous. The 

 valves (pi. 80, fig. 10) are very slender, separated for most of their 

 length; the edge is somewhat irregularly widened at the base, other- 

 wise finely serrate. 



The spicules of the tube feet are of the usual form of simple 

 more or less spinous rods. In the intestine they are partly irregular, 

 fenestrated plates, partly, in the esophagus and the adoral part of the, 

 intestine, small triradiate bodies (pi. 80, fig. lla-&). 



Fig. 21.— Apical system of Stylocidaris annulosa, new 

 species. X6 



