ECHINOMETRA VIRIDIS. 435 



Echinometra viridis 



! Echinometra viridis A. Ag., 1863, Bull. M. C. Z., I. 

 (See Part II. p. 284.) 



Pi. X'.f.i; PI. XXVI. f. 8-10. 



West India Islands. 



PARASALENIA. 



Parasaleuia A. Agass., 1863, Bull. M. C. Z., I. 



This genus seems to be an Oligopore among the Echinometradae, having 

 but three pairs of pores in each arc ; the poriferous zones are narrow ; the 

 obliquity of the test corresponds to that of Echinometra, and the spines 

 resemble those of the same genus ; there are but two rows of tubercles, of 

 a similar character to those of Echinometra, in the ambulacra! and inter- 

 ambulacral areas. The great generic difference is found in the small anal 

 system, which is closed by only four plates, as in the Arbaciadae. Buccal 

 membrane carrying minute spines and pedicellame, as in Echinometra. 

 Abactinal system large, characterized by the great development of the 

 genital plates and the limited number of anal plates. The jaws do not 

 differ from those of Echinometra proper. 



Parasalenia gratiosa 



! Parasaleuia gratiosa A. Ag., 1863, Bull. M. C. Z., I. 



Pi. III d . f. 1-2; Pi. VI. f. 14. 



At first sight, large specimens of this species would readily be mistaken 

 for true Echinometra. The test is elongate, elliptical, depressed, with two 

 principal vertical rows of primaries of nearly same size in the ambulacral 

 and interambulacral area. Poriferous zone narrow ; pores arranged in nearly 

 vertical arcs of three pairs. Actinostome large ; actinal cuts slightly lobed ; 

 poriferous zone somewhat petaloid at actinostome in older specimens. In 

 the interambulacral zone an irregular vertical row of secondaries separates the 

 primary row from the poriferous zones. Median line in both areas occupied 

 by miliaries and few small tubercles irregularly arranged in vertical zigzag 

 lines. Abactinal system extremely prominent ; anal system covered by 

 four large anal plates. Madreporic genital much broader than other genital 

 plates, wdiich are extremely elongate, carrying a single small secondary 

 tubercle near the anal system ; the genital openings large, elliptical, placed 



