THE ECHINOIDEA. 
43 
Bd. VI: 4) 
Non; Echinus margaritaceus. A. Agassiz. 1875. Zoological Results of the Kassier Exped. Echini. 
PI. III. Fig. 4 ( = Notcchinus magellanicus). 
1881. »Challenger* Echinoidea I. p. 117 (= Slereckinus dia- 
dema , pro parte). 
Slereckinus — Th. Mortensen. 1903. »Ingolf* Echinoidea I. p. ioi — 2 (= Sterechinus 
diadema). 
Echinus — R. Koehler. Expédition antarctique Française 1903 — 5. Stellendes, Ophiures 
et Échinides p. 30. Pi. I. 9. III. 29 — 30. IV. 40, 43 (= Sterechinus 
Neumayerï). 
In the »Ingolf» Echinoidea I, p. 10 1 — 2 I described, under the name of Ster echi- 
nus margaritaceus (Lamk.), a species which was really Sterechinus diadema (StüDER). 
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 »Voyage de la Frégate Vénus», 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. magellanicus , 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: »hemisphærico-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. » ruber ». 
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 of Echinus margaritaceus Lamk.: 
»Têt hémisphérique, déprimé; quatre rangs de tubercules dont les extrêmes sont les 
