58 HAWAIIAN AND OTHER PACIFIC ECHINI. 



A. Ag., which occurs in the Western Atlantic Ocean and Caribbean Sea, at 

 depths of 150-950 fathoms, though most commonly below 400 ; S. profundi 

 Duncan (commonly known as S. hastigera A. Ag., but as the two names refer 

 to the same species, the earlier must have precedence), which is apparently 

 almost cosmopolitan, having been reported from the north and south At- 

 lantic and from a number of stations in the East Indian region, at depths of 

 100-1850 fathoms, though most commonly below 1000 ; S. miliaris A. Ag., 

 which is known from various stations in the north Pacific, between the Gulf 

 of Panama and Japan, at depths of 670-1680 fathoms ; S. crassispina A. Ag. 

 and CI., which is known only from a single Hawaiian specimen, taken in 

 147-198 fathoms. There can be no doubt that goesiana Loven is based on a 

 very young specimen of either varispina or profundi, one cannot say which. 

 The species figured by Wy ville Thomson in " The Voyage of the Challenger : 

 The Atlantic " (Vol. I, figs. 31, 32), as varispina is a young profundi. The 

 specimens given by de Meijere (1904) and Doderlein (1906) as hastigera are 

 probably miliaris, but 5s those writers neither describe nor figure the relation 

 of the ocular plates to the anal system, the point cannot be positively deter- 

 mined ; the large number of ambulacral plates and the great height of the 

 test in Doderlein's specimen indicate miliaris. Doderlein now (1906) con- 

 siders his Japanese species, pacifica, as identical with hastigera, but it seems 

 more probable that it is miliaris ; this is certainly indicated by the abactinal 

 system (compare A. Agassiz, 1881, Challenger Echini, PI. 4, fig. 10 ; Doder- 

 lein, 1887, Jap. Seigel, PI. 11, fig. 9 ; and A. Agassiz, 1904, Panamic Deep Sea 

 Echini, PI. 16, fig. Jt). The species of this genus have pure white primary 

 spines, while the test, secondaries, and abactinal system are more or less 

 deeply colored with violet or purple pigment. They may be distinguished 

 from each other, when adult, by the following characters, but it must be 

 borne in mind that specimens under 9 mm. h. d. are young and cannot 

 be distinguished in all cases with certainty. 



Primary spines, long and slender, with numerous whorls of minute, delicate 

 teeth ; greatest thickness of shaft rarely equalling, and usually much less 

 than, diameter of milled ring. 



Coronal plates 8 or 9 (often 7 in specimens less than 9 mm. in di- 

 ameter) ; each of the two series of ambulacral tubercles consists 

 of 5 (3-6) larger tubercles actinally and 8 (7-10) smaller ones 

 abactinally; size small, h. d. seldom exceeding 10 mm. ; v. d., 

 .40-50 h. d., or, including the abactinal system, .60-. 70 h. d., but 

 usually less than .60 ; abactinal system usually less than .60 h. d. ; 

 actiual system usually less than .60 h. d varispina. 



