Bd. VI: 4) THE ECHINOIDEA. 43 



Non; Echinus margarilaceus. A. Agassiz. 1875. Zoological Results of the Hassler Exped. Echini. 



PI. III. Fig. 4 (= Notechinus magellanieus). 

 — — — 1881. >ChaIIenger> Echinoidea I. p. 117 (= Stereckinus dia- 



dema, pro parte). 

 Sterecliinus — Th. Mortensen. 1903. >Ingolf> Echinoidea I. p. lOI — 2 (= Sttrechinits 



diadcmd). 

 Echinus — R. KoEHLER. Expedition antarctique Française 1903 — 5. Stellérides, Ophiures 



et Échinides p. 30. PI. I. 9. III. 29 — 30. IV. 40. 43 (= Stcrechinus 

 Neumayiri). 



In the »Ingolf» Echinoidea I, p. loi — 2 I described, under the name of Sterecki- 

 nus margaritaceiis (Lamk.), a species which was really Sterecliinus diadenia (Studer). 

 The description was based mainly on material from the »Challenger» Expedition, 

 identified by Professor AGAS.SIZ as Echinus margaritaceus Lamk.; attention was 

 called to several important features of the species, hitherto unnoticed. De Loriol 

 having called my attention to the fact that in the figure of Echinus margaritaceus 

 in the Atlas of the »Voyage de la Frégate Vénus», Zoophytes PI. VI. i, all the ocular 

 plates are excluded from the periproct, by which fact alone it is shown beyond 

 question that the species mentioned by me under the name margaritaceus could not 

 really be identical with Lamarck's (Valenciennes) margaritaceus, I suggested in 

 the Appendix to Part I. (p. 177) that the Echinus margaritaceus Lamk. represented 

 in the Atlas of the »Venus» might be really the same as Eck. magellaniczis, because 

 the figure mentioned represents the species as having a primary tubercle on all the 

 ambulacral plates, like magellanieus, whereas in the species called margaritaceus by 

 the later authors there is a primary tubercle only on every second ambulacral plate. 

 This has been misunderstood by both KoEHLER, De Loriol and DöDERLEIN, as 

 if I regarded the Echinus margaritaceus AUCT. as the same species as magellani- 

 eus, and grave objections are raised against the view. This has, however, assuredly 

 never been my meaning; on the contrary, I find it quite correct that magellanieus 

 has been made the type of a separate genus. 



I must here give my reasons, why Lamarck's Echinus margaritaceus cannot 

 be the saine as the species described under this name by AgaS-SIZ in the »Revision 

 of Echini» and the »Hasslers-Echini. Lamarck's diagnosis: »hemisphaerico-depressus, 

 assulatus, ruber, verrucis albis eleganter ornatus; arearum majorum verrucis trans- 

 versim fasciatis» is certainly most unsatisfactory; but it contains, at least, one word 

 which decidedly does not suit with the species represented by Agassiz, viz. «rtiberT>. 

 Agassiz' species is white; and even if it is perhaps red in the living state, this does 

 not matter. Lamarck's specimen was a dried, naked test — but Agassiz' species 

 will never be found red when dried and denuded. Also the expression »areorum 

 majorum verrucis transversis fasciatis» does not suit with AgasSIZ' species. — Blain- 

 VILLE (loc. cit.) has given the following description oS. Echinus margaritaceus Lamk.: 

 »Têt hémisphérique, déprimé; quatre rangs de tubercules dont les extrêmes sont les 



