PSEUDOBOLETIA GRANULATA. 455 



neustes, but the outer vertical row of pores of the poriferous zone consists 

 of twice as many pores as the inner rows, and the pores are arranged in such 

 a way as to form arcs of four pairs of pores. The poriferous zone is compara- 

 tively no broader than in the true Toxopneustes. The actinal cuts are 

 marked, but less prominent than in the genus just mentioned. This is an 

 interesting genus, forming, as it were, a link between the Echinometradae 

 and Echinidae ; its position is still doubtful, and as no young specimens 

 have yet been examined, I am unable to state anything regarding the mode 

 of growth of the poriferous zone of this genus. 



Pseudoboletia granulata 



! Boletia granulata A. Agass., 18G3, Bull. M. C. Z., I. 



! Pseudoboletia granulata A. Agass., 1872, Rev. Ech., Pt. I. p. 153. 



The tubercles of the coronal plates are very uniform in size, closely packed, 

 covering nearly the whole of both areas, leaving bare only a small space 

 along the median lines near the abactinal pole. The secondaries are small, 

 far apart, and the rest of the coronal plate is closely covered by miliaries. 

 The spines are long, scarcely tapering, of remarkable uniformity in diameter 

 and length. The abactinal system is not materially different from that of 

 Toxopneustes, though in this species the anal system is covered by plates of 

 uniform size, except those immediately surrounding the anus, which are 

 smaller. The ten large buccal plates of the actinal membrane are re- 

 markably prominent and well developed, and carry over their whole surface 

 spines of considerable size, closely packed together, varying from 4 mm - to 5 mm ' 

 in length. The other buccal plates also carry each from two to three similar 

 small spines ; the whole buccal membrane thus being hidden from view. 

 The actinal cuts are slight, much less marked than in the species of Toxop- 

 neustes ; the adjoining interambulacral lip is large and broad, so that the 

 cuts appear almost like close comma-shaped openings. The pedicellaria? are 

 similar to those of Toxopneustes, though smaller, and do not attain the size 

 and prominence they do in that genus. The test is depressed, quite flat- 

 tened both above and below, slightly conical, regularly arched in profile. 



Sandwich Islands. 



