EVECHINUS CHLOROTICUS. 503 



converging towards the anal opening. Madreporic genital far larger than 

 the other genital plates ; genital openings large, near the outer edge. Geni- 

 tal plates carry one large secondary tubercle near the anal system ; smaller 

 ones fill the rest of plate. Ocular plates small ; the two reaching the 

 anal system carry secondary tubercles. Actinal cuts slight ; buccal mem- 

 brane thin, covered by very small distant plates, and a few well-separated 

 clusters of from six to eight larger plates in the extension of the ambulacra. 

 Spines rather stout, light green tipped with yellow ; color of the test greenish- 

 brown. In smaller specimens measuring not more than one fifth the above- 

 described specimen, — 18 mm - in diameter and 17 mm in height, with fourteen 

 coronal plates, — the poriferous zones are narrow in proportion to the size 

 of the test, we find only one row of pores separated by a vertical line of sec- 

 ondary tubercles from the outer rows of pores, which consist of two pairs 

 of pores placed obliquely near the ambitus, while near the abactinal region 

 the poriferous zone has all the features of (Psammechinus) Echinus ; the 

 changes in the arrangement of the poriferous zone at different stages of 

 growth will account for the position of this genus in so many different gen- 

 era by various authors. In the young the two principal vertical rows of 

 tubercles are more prominent than in older stages. 



No. of Abactinal Actinal Length of 



Coronal Platea Diameter. Height. System. System. Spine. 



25. 107. 62. 14. 24. 28. 



New Zealand. 



