278 THE VOYAGE OF H.M.S. CHALLENGEK. 



EXPLANATION OF THE PLATES. 



With the exception of Pis. XIII., XIX.% XXVIL, and XXVIIL, which were drawn 

 on stone by Mr A. Sonrel, of Pis. X.% X.^ XIX., XXIX., XLIV., XLV., drawn by Mr 

 Trouvelot, and Pis. XXXVI. , XXXVII. , XLIL, and XLIIL, drau-n by Mr Meisel, the 

 other plates were all lithographed by Mr Paulus Roetter, who had gained considerable 

 experience in drawing Echinids while making the plates of the Revision of the Echini. 

 The general views were cbawn by him dii-ectly on stone from nature ; the greater part of 

 the structural drawings were copies of sketches which I made myself to illustrate the 

 details of parts to be seen only from preparations of the test. The greater number of 

 the figures of Pedicellaria^, drawn on stone by Mr Meisel and by Mr Trouvelot, were 

 drawn by myself, with the exception of some drawings on the plates of Pedicellariee, and 

 of the sections of spines, drawn fi'om nature by Mr James H. Blake. The sections of 

 spines were made by Mr A. A. Julien, of the Columbia School of Mines. 



PLATE I. 



Cidaris [Dorocidaris) bracteata, A. Ag. (fig. 1), p. 37. 

 Fig. 1. Primary radiole. 



Cidaris trihxdoides, Bl. (figs. 2-6), p, 36. 



,, 2. Small specimen of Cidaris ;n6tt?oic?es, measuring 18 mm. in diameter, in which 

 the radioles have the shape characteristic of Phyllacanthus veiiicillata. 



,, 3. A single primary radiole magnified (-^). 



„ 5. A smooth primary radiole similar to those of the lower side of the test in Cidaris 

 trihuloides (f ). 



„ 6. Another primary radiole, in which the verticillation is not so marked as in fig. 3 (f ). 



Goniocidaris Jlorigera, A. Ag. (figs. 7-20), p. 46. 



,, 7. A specimen (n.s.) seen from the abactinal side, in which the spines are all of the 



shape of figs. 8-11, and quite uniform in their aj)pearance. 

 ., 8, 9. Primary radioles, with sharp spines of fig. 7. 



