38 NATURAL HISTORY BULLETIN 



row has five or six spines and the doso-lateral ones fewer. The 

 papular pores are small and numerous dorsally ; few and mostly 

 isolated below the inferomarginal spines. A row of small inter- 

 actinal plates separates the inferomarginal plates from the 

 adambulacrals and some of these bear rudimentary spines, and 

 many have small solitary papulae between them. 



The adambulacral plates have three small spines in an oblique 

 row; the inner one is very small and deep in the furrow; the 

 outer ones are webbed together longitudinally. Color, when dry, 

 pale yellowish brown. The madreporite is small, round, rough 

 with minute spinules. 



Teratology. 



A regular four-rayed specimen was obtained by the Bahama 

 Expedition at the Great Bahama Bank, in shallow water. May 

 17, 1893. 



The radii are 13™™ and 53™™ ; ratio, 1 :4.1. The dorsal spines are 

 rather numerous, subequal, of moderate size and acute. They 

 do not form definite or obvious rows, but appear as if in about 

 six or seven zigzag and irregular rows proximally. They are 

 not crowded. 



Papular areas, between them, are large, with many rather large 

 pores; these areas form about six irregular rows. Additional 

 ones exist between the rows of marginal spines and scattered 

 papulge occur between the inferomarginals and the adambula- 

 crals, and between the interactinals. 



The rows of superomarginal spines are not clearly distinct 

 from the dorsals, being of the same size and form and the rows 

 are irregular. The inferomarginal row is more regular, but the 

 spines are of the same size. This row is near the adambulacral 

 plates and about four of the adambulacral plates correspond 

 to each of these spines in the amount of space occupied. There 

 are about twenty to twenty-four of these spines in each row. 

 Proximally there is a short irregular intermarginal row, and also 

 a row of small interactinals, the latter mostly spineless. 



The adambulacral plates mostly bear three partially webbed 

 spines. Two on the outer surface are subequal, one nearly 



