292 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



spines are stouter and the tubercles and areoles on the upper plates 

 are more normally developed. In some of them also the ocular 

 plates are smaller than usual, and the ambulacra have a narrow inter- 

 poriferous zone. Had these specimens been found alone, together 

 with the typical form, I should not have hesitated to regard them as 

 a seperate species. But the rich material at hand shows all transi- 

 tional forms, so that it becomes quite impossible to distinguish the 

 form with the stouter spines even as a variety. 



Remarks. — The closest relationships of the present species are with 

 Stylocidaris tiara (Alcock) . It agrees with that species in the general 

 character of the primary spines, which are in both provided with 

 relatively few (7 or 8 in tiara, 9 or 10 in effluens) sharp prominent 

 ridges, the surface of the spines otherwise being set with very short 

 simple hairs; but these ridges are entire in tiara, while in effluens they 

 are more or less coarsely serrate. Also in tiara the upper areoles are 

 more or less effluent; but then the larger ambital tubercles are finely, 

 but rather distinctly, crenulate in tiara, which they are not in effluens. 

 Otherwise the characters of the two species are very much the same, 

 but the differences indicated are sufficent to prove that they can not 

 be regarded as identical. 



It does not appear that S. effluens is more closely related to any 

 other recent species. The peculiar effluent character so conspicuous 

 in some specimens of this species recalls to some degree the fossil 

 Stereocidaris sceptrifera (Man tell) ." The character of the effluence 

 of the areoles in this fossil form is, however, different from that of 

 the recent form, and there is absolutely no close relationship between 

 the recent and the fossil species. 



STYLOCIDARIS REINI (Doderlein) 



Plate 66, fig. 2; plate 67, fig. 2 

 Cidaris (Dorocidaris) reini Doderlein, Die japanischen Seeigel, I, Familien 



Cidaridae und Saleniidae, 1887, p. 7, pi. 4, figs. 1-7; pi. 8, figs. 4, a-d. 

 Cidaris (Cidaris) reini de Meijere, Die Echinoidea der Siboga-TLxped., 1904, 



p. 5, pi. 1, figs. 2-3; pi. 11, figs. 103-108. 

 Dorocidaris reini A. Agassiz and H. L. Clark, Mem. Mus. Comp. Zool., 



vol. 34, No. 1, 1907, p. 10, pi. 3, figs. 1-14. 

 Tretocidaris reini H. L. Clark, The Cidaridae, 1907, p. 207. 

 Stylocidaris reini H. L. Clark, Cat. Recent Sea-urchins Brit. Mus., 1923, 



p. 24. 



Localities. — Station 5367; Verde Island passage; Malabrigo Light 

 bearing N. 81° E., 8 miles distant (lat. 13° 34' 37" N., long. 121° 07' 

 30" E.) ; 329 meters; sand; February 22, 1909 (8 specimens, Cat. No. 

 E. 1317, U.S.N.M.). 



Station 5617; Dodinga Bay, Gillolo; Ternate Island (SE.) bearing 

 S. 45° W., 7 miles distant (lat. 0° 49' 30" N., long. 127° 25' 30" E.) ; 



uSee Th. Wright, Monograph of the British Fossil Echinodermata from the Cretaceous Formations. 

 1802-1882, pi. 6, fig. 1. 



