260 Bulletin Vanderbilt Marine Museum, Vol, VI 



Also, as reported by Dr. Mortensen, the tridentate pedicel- 

 lariae of the two species are different, those of trigonarius being 

 composed of bluntly pointed valves, which are in contact along 

 the greater portion of their lateral and apical margins. 



References : Echinus trigonarius, Lamarck, J. B., Hist. Anim. 

 sans Vert., t. Ill, 1816, p. 51. 



Heterocentrotu^ trigonarius, Brandt, Prodom. descript. Anim., 

 1835, p. 266 (66).— Agassiz, A., Mem. Mus. Comp. Zool., vol. 

 VII, 1873, p. 133, 430, pi. 3d, fig. 6.— DE Meuere, J. C. H., 

 "Siboga"-Expeditie, Echinoidea, Livr. 14, Monogr. 53, 1904, 

 p. 102 (with extensive bibliography). — Mortensen, Th., 

 "Ingolf" Echinoidea, I, 1903, p. 129.— Clark, H. L., Mem. 

 Mus. Comp. Zool., vol. XXXIV, 1912, p. 379, pis. 118-120. 



