451 



ADDITIONAL NOTES ON THE ECHINOIDEA. 



Since the commencement of this Monograph in 1855, I have obtained additional 

 information on many of the species described therein, and have lately discovered some 

 new forms. I purpose, therefore, giving notes on the described species under their 

 respective names, and in the same order as they were originally figured in the body of 

 the work. The descriptions of the new species which are lithographed in the supplementary 

 plates will be found among the genera to which they belong. 



CIDARID^. 



CiDARis PowLERT, Wriglit. Supplement, PI. XLII, fig. 1, «, h, c, d, e,f. 



The fine specimen figured in this plate was found in a mass of pea-grit on Leckhamp- 

 ton Hill ; the block containing the urchin had been long exposed to the atmosphere, and the 

 test, in consequence, is a little weathered in parts. It has seven primary spines, more 

 or less perfect, with several secondary spines attached in situ to the test. The primary 

 spines (PI. XLII, fig. 1 e) are long, slender, and nearly of a uniform diameter through- 

 out, apparently tapering very little towards their free extremity. The head is strongly 

 crenulated, the milled rim prominent, the neck smooth and of the same thickness 

 as the body ; the surface of the long stem is covered with short, thorn-like tubercles, 

 which have their points directed forwards. As all the spines are more or less fractured, 

 their proportionate length to the diameter of the test cannot be ascertained. The secondary 

 spines (fig. 1 /) are small and spatulate; many of them are still adherent to the 

 plates of the test. Pig. ] b represents an inter-ambulacral plate, with its primary tubercle 

 and circle of areolar granules ; fig. 1 c, a profile of one of the large tubercles, showing 

 the prominence of the crenulations ; fig. 1 d, one of the jaws of the lantern, magnified 

 twice. 



CiDARis Smithii, Wright. Supplement to pages 50 — 52. 



When I figured the very fine specimens of PI. II, considerable doubts existed relative 

 to the locality whence they were collected. My lamented colleague. Professor Porbes, 



59 



