TEMNOPLEURUS TOREUMATICUS. 463 



Temnopleurus toreumaticus 



! Cidaris toreumatica Klein, 1734, Nat. Disp. Ech. 

 ! Temnopleurus toreumaticus Agass., 1841, Mon. Scut. 



PI VIII". f. 4-5. 



This is one of the earliest species of Echini figured by the old authors, 

 and one readily recognized. Klein's original specimen was in excellent con- 

 dition, the abactinal system even being completely preserved. The anal 

 system is of moderate size, covered by a large number of irregular plates ; 

 the original single anal plate of the young can still be distinguished from the 

 others by its greater size in specimens measuring over 50 mm in diameter. The 

 genital ring is broad ; all the ocular plates are excluded from the anal area ; 

 the genital plates are solid, prominent, triangular, with a well-marked genital 

 opening towards the extremity of the irregularly triangular genital. The 

 madreporic genital is only slightly larger than others ; the ocular plates have 

 rounded edges, with a deep pit in the angle of junction with the genital 

 plates. 



In the interambulacral space there are for each plate along the horizontal 

 suture two deep rectangular furrows, separated by the principal row of 

 primary tubercles. The outer pit about half as small as the pits running to 

 the median line. At the median line the pits terminate in an almost vertical 

 line, towards the other extremity the pits are somewhat pointed ; the shape 

 of the outer pit is the reverse, being cut off square towards the poriferous 

 zone. The principal vertical row of primaries forms a connected line from 

 the abactinal pole to the actinostome, while in all the other vertical rows the 

 tubercles are disconnected by the deep pits of the sutures of the plates. 

 There are at the ambitus of the specimen measuring 55 mm four vertical rows 

 of tubercles of nearly uniform size, — all, however, except the principal one 

 diminishing rapidly in size towards the abactinal pole, — which extend a little 

 way above the ambitus as minute secondaries. The tubercles of the princi- 

 pal vertical rows are surrounded by numerous minute secondaries, and near 

 the ambitus the tubercles of the other vertical rows are similarly circum- 

 scribed. Below the ambitus the tubercles are very uniform, gradually de- 

 creasing in size to the actinostome ; the furrows on the actinal surface become 

 mere small rectangular pits along the median line and next to the poriferous 

 zone. In the ambulacral space there are two principal vertical rows of tuber- 

 cles adjoining the poriferous zone ; the furrows run from the base of the tuber- 

 cles to the median line, as in the median interambulacral space. These primary 



