REPORT ON THE ECHINOIDEA — MORTENSEN 285 



smooth, with merely the point curved. The fourth is transitional to 

 the ambital spines. 



The secondary spines are in general slender. The scrobicular spines 

 are about 3 mm. long, flattened, gently narrowing toward the rounded 

 point; the marginal ambulacral spines are about 2 mm. long, very 

 slender, and setaceous; the proximal ones are broadened and concave 

 at the point. The miliary spines are simply setaceous. The second- 

 aries are in general erect, only the scrobicular ones being somewhat 

 appressed, but not forming a close mail around the base of the 

 primaries. 



Large globiferous pedicellariae were not observed. Small globif- 

 erous pedicellariae are rather abundantly developed; they are partly 

 of the usual form, partly much elongated, so as to resemble tri- 

 dentate pedicellariae, and partly of a somewhat coarser type (pi. 78, 

 figs. 3-5). All of them have only a short and inconspicuous end 

 tooth, which is sometimes scarcely at all distinct. The large coarse 

 tridentate form, often found in goniocidarids, has not been observed 

 here. The spicules are of the usual form — simple, slightly spiny rods. 



In color the primaries are whitish with a pale pinkish tint, espe- 

 cially in the basal part. The secondaries are yellowish white. The 

 skin of the test is of a yellowish-red tint, while the naked test is 

 perfectly white. 



Remarks. — This species to some degree resembles Goniocidaris (Cyr- 

 tocidaris) tenuispina, but differs so markedly from it, especially in the 

 character of its primary spines, that it is out of question to include 

 them in the same genus. On the other hand, it recalls to a still more 

 marked degree the genus Aporocidaris in its very long and slender 

 spines, its large apical system, etc. But it also is very conspicuously 

 different from the species of that genus, especially in the much more 

 numerous ambulacral plates and the pedicellariae, so that it seems 

 equally unjustifiable to refer it to Aporocidaris. The only possible 

 course, therefore, seems to be to make it the type of a separate genus, 

 Psilocidaris. The fact that it is about equally closely related to 

 Goniocidaris (Cyrtocidaris) on the one hand and to Aporocidaris on 

 the other affords proof that the affinities of Aporocidaris must be 

 with the goniocidarids, and we thus get a very satisfactory solution 

 of the hitherto rather obscure question concerning the relationships of 

 the genus Aporocidaris. 



Genus STYLOCIDARIS Mortensen 



STYLOCIDARIS EFFLUENS, new species 



Plate 59, fig. 3; plate 62, figs. 1, 2; plate 65, figs. 1-4; plate 75, figs. 1, 2; plate 



80, figs. 1-6 



Localities. — Station 5194; off northern Cebu; Chocolate Island 

 bearing N. 66° W., 8 miles distant (lat. 11° 15' 30" N., long. 124 



