316 HAWAIIAN AND OTHER PACIFIC ECHINI. 



sphtxroides, but there is some doubt regarding Belli Doderlein. We have a 

 beautiful specimen of the latter, or one at least from "Challenger" Station 188, 

 and Mortensen (1904, Dan. Exp. Siam: Ech., p. 68) asserts that the Salmacis 

 from that station is Belli. Moreover it answers well to the published descrip- 

 tions, save for the following details: the globiferous pedicellariae do not "agree 

 exactly with" those of bicolor as Mortensen says but, are easily distinguishable 

 (PI. 93, figs. 33-36) ; the coronal (interambulacral) plates are not essentially 

 different in proportions from those of sphoeroides, for they are scarcely five times 

 as wide as high, while in one of our sphceroides they are more than five times as 

 wide as high, instead of less, as usual. Whether the differences in color, tri- 

 dentate pedicellarise, actinal primaries, and gill-cuts really have any significance 

 remains to be determined. So far as can be determined, the following species 

 may be accepted and distinguished from each other thus : 



Vertical diameter of test exceeds one half horizontal; all oculars exsert; each ambula- 



cral plate with a primary tubercle close to the poriferous area. 

 Primary spines not banded, greenish or light colored at base, becoming reddish or 



purple distally (or for most of their length) but sometimes with light tips. 

 Coronal plates separated from each other by distinct sutures, the edges of 



which may be slightly bevelled virgulata. 



Coronal plates separated from each other by deep horizontal furrows, the sides 



of which are more or less vertical Alexandri. 



Primary spines banded, usually conspicuously so. 



Primary spines more or less bright red, especially abactinally, at least at base; 



small spines red bicolor. 



Primary spines green at base, at least abactinally. 



Primaries, distal to green base, not rose-red; valves of tridentate pedicel- 

 lariae very narrow; actinal primaries not specially widened at tip; 



gill-cuts deep sphceroides. 



Primaries, distal to green base, rose-red; valves of tridentate pedicel- 

 laria;, broad; actinal primaries noticeably widened at tip; gill-cuts 



insignificant Belli. 



Vertical diameter of test less than one half horizontal; ocular I insert or nearly so; only 

 every other ambulacral plate (at least in mid-zone) with a primary tubercle close 

 to the poriferous area. 



Primary spines white or greenish with 2 or 3 broad bands of purple or purplish red, 

 or the dark color may predominate, the white disappearing and the bands 

 becoming indistinct; secondary and miliary spines not at all vermilion-red . . Dussumieri. 

 Primary spines green or greenish; actinal ones with 2 or 3 indefinite broad bands of 



purplish brown; secondaries and miliaries vermilion-red at base erythracis. 



