LYTECHINUS EUERCES. 247 



spines stout and blunt; size moderate, up to 40 mm. 



h. d piclus. 



Abactinal interambulaeral plates largely bare, usually with 

 only 3 or 4 small tubercles; primary spines slender 

 and pointed; size large, up to 80 mm. h. d. 

 Color variable, but rarely deep violet ; primaries mod- 

 erately slender; ocular IV seldom insert (in 

 only 8 per cent of the specimens) . 

 Colors prevailingly green and white; primary 



spines rather slender variegatus typicus. 



Color prevailingly dull pink; primary spines 



stouter variegatus carolinus 



Color deep, rich violet; primary spines very slender; 

 ocular IV often insert (28 per cent of the speci- 

 m ens) variegatus atlanticus. 



Lytechinus euerces, 1 sp. nov. 

 Plates 93, figs. 4, 5; 98, figs. 3, 4; 107, figs. 4-6. 



The largest of the specimens (PL 107, figs. 4-6} measures 32 mm. in diameter 

 while the height of the test is 22.5 mm. There are 18 interambulaeral plates in 

 each column and 23 ambulacral plates in each half-area. The longest primary 

 from just below the ambitus, is only about 6 mm. in length. The abactinal 

 system is 8 mm. in diameter and the actinostome 12 mm. A smaller specimen, 

 18 mm. in diameter, has the test 12 mm. high, the abactinal system less than 5 mm. 

 across and the actinostome 8 mm. There are 14 interambulaeral and 16 ambula- 

 cral plates in each column. In a still smaller specimen, 10 mm. in diameter and 

 6 mm. high, the abactinal system is 4 mm. across, the actinostome 6 mm., and 

 there are 8 interambulacral and 10 ambulacral plates in each column. 



The periproct (PL 98, fig. 4) is moderately large, decidedly exceeding a 

 genital plate in area. It is covered by a dozen or more plates, of which those 

 adjoining the anus are quite small; the outer series are much bigger and the one 

 adjoining the left anterior genital plate is so much the largest it may properly 

 be called a suranal; in the largest specimen, it carries a well-developed secondary 

 tubercle and spine. The genital plates are of approximately equal size, though 

 the madreporic plate may be a trifle the largest. They usually form a closed 

 ring, but 1 and 5 may be separated. They are noticeably bare, carrying only 

 1-3 secondary tubercles, situated near the proximal margin. The pores are 

 circular and quite large, in the distal part of the plate. The oculars are small 



= well protected. 



