Bil. VI: 4 ) 
THE ECHINOIDEA. 
4 l 
The specimens from Stat. 2 (off the La Plata) correspond to the var. Hassleri 
of DÖDERLEIN in being somewhat lighter in colour than the typical form. The 
spines are a little longer than is generally the case in the typical specimens, but, 
as seen from the measurements, they may be quite as long in the typical form. 
Regarding the number of the coronal plates, which is mentioned by DöDER- 
LEIN as the most important character, the variety having somewhat fewer plates 
than the typical form, the enumerations given above show that in these specimens 
at least, there is no such constant difference. On the other hand I find the test in 
these specimens generally distinctly pentagonal, whereas in the typical form it is 
generally quite round. Upon the whole I think it scarcely possible to maintain this 
form as a distinct variety; it is probably only a slightly modified deep-water form. 
(The station 2 is near the locality of type specimens of the Var. Hassleri .) 
As will be remarked from the list of synonyms given under this species, I 
think it not improbable that Notech, magellanicus is really the same species as the 
Echinus margaritaceus Lamk. figured by VALENCIENNES in the Atlas of the »Venus» 
(Zoophytes PI. 6. Fig. i). Since, however, this can no longer be determined with 
certainty, the specimen having been lost, the name magellanicus will have to be 
kept. As for the species called margaritaceus by AGASSIZ and DÖDERLEIN, it is 
certainly not identical with Lamarck’s species, but this is treated more fully under 
Sterechinus Agassizii (p. 43). 
It is with full right that DÖDERLEIN has removed this species from the genus 
Sterechinus , to which genus I had referred it in the Ingolf Echinoidea I. Un- 
doubtedly the genus Sterechinus thus becomes much more natural and well limited. 
That magellanicus agrees in several respects with Pseudechinus albocinctus I had 
perfectly realized (Op. cit. p. 106 ), but especially De Loriol emphasizes the cor- 
respondence between these two species. It must be agreed that one might indeed 
be tempted to refer them to one and the same genus. After all I must, however, 
join DÖDERLEIN in making magellanicus the type of a separate genus, mainly on 
account of the giobiferous pedicellariae, which have in albocinctus only one lateral 
tooth, as in the family Echinometridæ. Besides, the curved actinal spines and the 
two kinds of giobiferous pedicellariae in magellanicus are rather conspicuous diffe- 
rences from albocinctus (I have been unable to find more than one form of giobi- 
ferous pedicellariae in albocinctus , having carefully examined the several specimens 
at my disposal); on the other hand, the fact that in albocinctus the giobiferous pedi- 
cellariæ have double glands as in magellanicus is noteworthy. It seems, indeed, that 
the two species: magellanicus and albocinctus show the way from the Echinidæ to 
the Echinometridæ. — In case it be ultimately proved that these two species cannot 
be referred to different genera — or even different families — magellanicus must be 
referred to the genus Pseudechinus , to which Notechinus will then be a synonym. 
6 — 100133. Schwedische Südpolar- Expedition igoi — içoj. 
