MESPILIA. 477 



MESPILIA. 



Mespilia Des., 1846, in Agass., C. R. Ann. Sc. Nat, VI. 



Echini with thin globular test ; tubercles small, imperforate, and crenulate ; 

 the median areas bare ; tubercles pushed to the sides of the coronal plates 

 on the upper surface of the test, on the actinal surface they are closely 

 packed together. Sutural pores in the angle of the coronal plates. Porif- 

 erous zone broad, pores arranged in two irregular vertical rows ; the outer 

 row has fewer pores than the inner row. Buccal membrane bare ; abac- 

 tinal system moderately large ; spines hair-like, very slender, not long ; 

 the bare spaces of the ambulacral and interambulacral areas closely packed 

 with innumerable pedicellarise, supported upon short steins. Actinostome 

 decagonal, of rather small size. Auricles are high, with low connecting 

 ridge and large auricular foramen. The pyramid of the teeth is remarkable 

 for the small foramen on the upper part of the face of the pyramid. 



Mespilia globulus 



Cidaria granulata Leske, 1778, Kl. Add. 



! Mespilia globulus Agass., 1846, C. R. Ann. Sc. Nat., VI. 



PI. Vl.f.i; PI Vlir.f. is- u; PL VIII'. f. 14; PL XXXVIII. f. ss, as"'. 



The only species thus far known of this genus does not reach a large size, 

 and when covered with spines is a most graceful Sea-urchin. The broad, 

 bare areas of the interambulacral spaces are of a dark green color (in alco- 

 hol), separated by a belt of closely packed spines of uniform length ; the 

 spines are of a light green at the base, and towards the extremity banded with 

 white and purple. Between the broad belts are the narrower bare belts of 

 the ambulacral areas, separated from the poriferous zones by narrower zones 

 of spines. The bare spaces reach the ambitus ; the whole lower surface is 

 uniformly tuberculated and covered by rather larger and stouter spines than 

 those above the ambitus. Anal system large, covered by a small number of 

 rather large plates carrying each a minute tubercle ; genital ring narrow ; 

 genital openings large ; genital plates of uniform size, laterally elongate, 



