488 HEMIPEDINA. 



rapidly in size in both areas as they approach the apex. The coronal plates 

 above the ambitus are sparsely covered by secondary tubercles. The smaller 

 tubercles, arranged in an irregular circle round the main tubercles, are not 

 crenulated, while the small secondaries, arranged on each side of the princi- 

 pal vertical rows in the interambulacral space, are crenulated. A vertical 

 row of secondaries extends from the actinostome to slightly above the 

 ambitus. In the ambulacral space there are only small unerenulated 

 secondary tubercles arranged irregularly round the primaries. In the abac- 

 tinal system the genital ring is of uniform width, the madreporic genital 

 being only slightly larger than the others. Two large ocular plates reach 

 the anal system, which is covered by plates carrying a few tubercles; these 

 plates diminish in size towards the eccentric anal opening. Tubercles of the 

 abactinal system not crenulated, and principally confined to the anal edge 

 of the abactinal plates. 



The primary spines are long, stout, tapering gradually, with a fine longi- 

 tudinal striation commencing at the milled ring. The color of dried speci- 

 mens is yellowish, with darker- colored spines. The auricles are high, slight, 

 with low connecting ridges. Teeth present no marked feature as distinguish- 

 ing this type of Echini from the Echinidae proper. 



Japan. 



(PSEUDODIADEMA.) Hemipedina. 



Hemipedina Wright, 1855, Brit. (Jul. Eih. 

 (Sec Part II. p. 291.) 



Hemipedina cubensis 



' Caenopedina cubensis A. Agass.. 1869, Bull. M. C. Z.. I. 

 '.Hemipedina cubensu A. Agass., 1872, Rev. Ech., Pt. I. p. 132. 

 (See Part II. p. 291.) 



PL IILf. 1-7; PL XXXVI. f. 12. 



Straits of Florida. 



