Bd. VI: 4) 



THE ECHINOIDEA. 



43 



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



PI. III. Fig. 4 (= N'otechintis magellankus). 

 — — 1881. >Challenger> Echinoidea I. p. 117 (= Sterechinus dia- 



dema, pro parte). 



Sterechinus — Th. Mortensen. 1903. »Ingolf> Echinoidea I. p. 101 — 2 (= Sterechinus 



diadema). 



Echinus — R. Koehler. Expedition antarctique Frangaise 1903 — 5. Stellerides, Ophiures 



et Fxhinides p. 30. PI. I. 9. III. 29 — 30. IV. 40, 43 (= Sterechinus 

 Neitmayeri). 



In the »Ingolf» Echinoidea I, p. 101 — 2 I described, under the name of Sterechi- 

 nus margaritaceus (LAMK.), a species which was really Sterechinus diadema (STUDER). 

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

 identified by Professor AGASSIZ 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 sVoyage de la Eregate Venus», Zoophytes PI. VI. 1, 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 Ech. mage/lanicus, because 

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

 ambulacral plates, like magellanicus, 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 DODERLEIN, as 

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

 cus, 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 magellanicus 

 has been made the type of a separate genus. 



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

 be the same as the species described under this name by AGASSIZ in the »Revision 

 of Echini» and the »Hassler»-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. »ruher*. 

 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. Al'so the expression »areorum 

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

 VILLE (loc. cit.) has given the following description of Echinus margaritaceus LAMK.: 

 »Tet hemispherique, deprime; quatre rangs de tubercules dont les extremes sont les 



