Nomen clature of Ech inoids. 119 



' D'Amboinsche Rariteitkamer/ pi. xiii. fig. 4, with C. im- 

 perialis really appears very rash. It may equally well (or 

 badly) represent almost any species of Cidarid. Lambert 

 and Thiery evidently base their identification of the figure 

 with imperialis, Lamk., on the supposition that this is " le 

 seul Cidaris veritable des iles de la Sonde." That this 

 is wrong need not be discussed at any length ; it will be quite 

 sufficient to call to mind the fact that De Loriol, in his paper 

 " Echinodermes de la baie d'Amhoine" (Revue Suisse de 

 Zool. i., 1893), records three Cidarids from Amboina, viz. 

 Cidaris meiularia, Lamk., Rhabdocidaris annulifera, Lamk., 

 and Rhabdocidaris imperialis, Lamk. The figure quoted in 

 Kumphius's work might equally well be identified as repre- 

 senting any of these three species ! The identification main- 

 tained by Lambert and Thiery, by which is rejected what is 

 otherwise almost unanimously accepted, is thus based on an 

 old bad figure, of which no one can say with certainty which 

 species it really represents' — "on reste ainsi dans la tradition 

 des auteurs et Fon n'est pas oblige" de proceder au bouleverse- 

 ment general de la nomenclature" ('Notes Echinologiques/ 

 i. p. 30). 



In the " Siam " Echinoidea, i. p. 38 *, I have maintained 

 that the name Plesiodiadema, Pomel, must be used instead 

 of Derviatodiadema, A. Agassiz — the former having been 

 established in 1883 f for Aspidodiadema microtuberculatum, 

 the latter in 1898 \ for the species " having only small 

 secondary tubercles in the ambulacral areas " ; no type 

 species is named, but it is evident that also microtuberculatum 

 must be included in the genus, and accordingly Dermato- 

 diadema becomes a synonym only of Plesiodiadema. Now it 

 is true that Pomel was confused in his diagnosis of the two 

 genera Aspidodiadema and Plesiodiadema, saying of Aspido- 

 diadema " ambulacre ties etroit, reduit a des simples granules, 

 comme clans Cidaris" and of Plesiodiadema " ambulacres 

 . . . pourvus d'un rang double de petits tubercles." Under 

 Aspidodiadema he names the species tonsum, under Plesio- 

 diadema, microtuberculatum. On account of this confusion in 

 the diagnoses the name Plesiodiadema is rejected by Agassiz 

 (' Panamic Deep-sea Echini/ p. 59), Doderleiii ( f Echinoidea 



* " The Danish Expedition to Siam, 1899-1900, Zoological Results, 

 II., Echinoidea I.," Mem. Acad. R. d. Sci. Oopenliague, 7 ser., i. (1904). 



t A. Pomel, ' Classification mdthodique et genera des Echinides 

 vivants et fossiles,' 1883, p. 106. 



I " Preliminary Report on the Echini. Reports on the Dredging 

 Operations ... U.S. Eish Comm. Steamer 'Albatross,' 1891, xxiii.," 

 Bull. Mus. Comp. Zool. xxxii. no. 5, 1898, p. 76. 



