STRONGYLOCENTROTUS DROBACHIENSIS. 441 



The color of test is light brownish-pink ; the spines are short, slender, of 

 uniform color, somewhat darker than the test, and of very even length over 

 the whole abactinal j)art of the test, giving the species much the facies of 

 Sphaer. granulans. 



Japan. 



Strongylocentrotus Drdbachiensis 



IV Echinus Drdbachiensis Mull., 1776, Zool. Dan. Prod. 

 1 Strongylocentrotus Drdbachiensis A. Ao., 1872, Rev. Ech., Pt. I. p. 162. 

 (See Part II. p. 277.) 



PL IV. f. 2, 3, 6; PL VI. f. g; PL IX. ; PL X ; PL XXIV. f. 15-24; PL 

 XXVII f. 1-5; PL XXXVIII f. 13, 14. 



North European ; North Pacific ; Northeast Coast of North America. 



Strongylocentrotus eurythrogrammus 



! Echinus eurythrogramrnus Val., 1846, Voyage Venus. 



! Strongylocentrotus eurythrogrammus A. Ac, 1872, Rev. Ech., Pt. I. p. 163. 



PL V.f. 2-4. 



Test regularly arched, subglobular. Two principal vertical rows of tubercles 

 in the interambulacral and ambulacral spaces ; a well-defined vertical row 

 of small tubercles separating the poriferous zone from the primary tubercles 

 in the interambulacral space. Two irregular median vertical interambu- 

 lacral rows. Coronal plates closely crowded with small secondaries ; the 

 intervening space again filled with closely packed miliaries surrounding them. 

 The same arrangement extends to both the median ambulacral and the porif- 

 erous zones. The main ambulacral tubercles are of the size of the median 

 interambulacral row, and the median ambulacral rows of the same size as the 

 secondaries filling the space between the primaries in the interambulacral 

 space. Poriferous zone broad ; pores arranged in oblique arcs separated by 

 irregular rows of secondaries arranged obliquely, and forming indirectly 

 a vertical line of small secondaries on the outer sides of the main vertical 

 ambulacral row. Poriferous zone slightly diminishing in width towards the 

 actinostome. 



Abactinal system moderately compact, much like that of S. tuberculatus, 

 but less tubercular. Anal system covered by small plates less numeror.s 



