ECHINODERMATA. 295 



Family ANANCHYTIDAE. 

 Genus ANANCHYTES Mercati. 



Ananchytes oval is Clark. 

 Plate XIIL, Figs. 1-8. 



1893. Ananchytes oval-is Clark, Johns Hopkins Univ. Circ., vol. 



12, No. 103, p. 52. 

 1893. Ananchytes ovalis Clark, Bull. U. S. G. $., No. 97, p. 74, 



pi. 36, figs, i a-h. 



Description. Test subovate, somewhat pointed posteriorly, 

 ventral side nearly flat, curving inward to the oral opening, with 

 a rounded ridge joining the anal and oral openings; the sides full 

 and rounded at the ambitus, the dorsal surface convex. Ambu- 

 lacral areas broad and flat, attaining their greatest width just 

 above the ambitus, the pores subelliptical in outline, the longer 

 axes of those of each pair directed at an angle to each other. 

 Interambulacral areas broad. The surface of both ambulacral 

 and interambulacral plates covered with small tubercles, between 

 which are numerous microscopic granules. Apical disk situated 

 slightly in front of the center, elongate; the four genital plates 

 large and distinctly perforate, the right anterior one, which serves 

 as the madreporite, is much larger than any of the others, being 

 several times the size of the left anterior one with which it is in 

 contact, the posterior ones of nearly equal size. Oral opening 

 transversely subelliptical, situated near the anterior margin. Anal 

 opening oval, situated on a marked protuberance on the posterior 

 margin. 



The dimensions of a complete individual are: length, 43.75 

 mm.; width, 37.5 mm.; height, 31.25 mm. 



Remarks. This species is the only known American repre- 

 sentative of the genus, and it differs from the European species 

 in its more ovate and less elevated form. 



Formation and locality. Vincentown limesand, Vincentown 

 (Clark). 



Geographic distribution. New Jersey. 



