12 
TH. MORTENSEN, 
(Schwed. Südpolar-Exp. 
Stereocidaris 
A ustrocidaris — 
(?) Cidaris — 
Stereocidaris — 
Austrocidaris 
canaliciilata. L. Döderlein. 1906. Echinoiden d. deutschen Tiefsee-Expedition p. 96, 102. 
R. Koehler. 1907. Astéries, Ophiures et Échinides recueillis dans les mers 
australes par la »Scotia» (1902 — 1904). Zool. Anzeiger. XXXII. p. 143. 
H. Lym. Clark. 1907. The Cidaridæ. Bull. Mus. Comp. Zool. LI. p. 212. 
— F. Jeffr. Bell. 1908. Echinoderma. National Antarctic Expedition. Natural 
History. Vol. IV. Zoology, p. 5. 
R. Koehler. 1908. Astéries, Ophiures et Échinides de l’Expédition antarctique 
nationale Écossaise. Trans. R. Soc. Edinburgh. Vol. XLVI. p. 615. 
Th. Mortensen. 1909. Echinoiden d. deutschen Südpolar-Expedition p. 37 — 39. 
Non: Cidaris nutrix Wyv. Thoms. 
Goniocidaris membranipora StüDER. 
Stereocidaris Lorioli Mrtsn. 
The rather intricate synonymie history of this species has probably at length come 
to an end; after having been referred in the course of time to no less than 6 different 
genera it has now been made the type of a new genus, Austrocidaris , and there it 
will doubtless remain. To be sure the author of the genus, Professor H. Lym. CLARK, 
thinks it only slightly different from Dorocidaris — »were it not for their geo- 
graphical isolation it would hardly be worth while to separate these three small 
species from Dorocidaris», he says (Op. cit. p. 212). This conclusion, however, can 
only be arrived at, when the characters afforded by the pedicellariæ are left out of 
consideration. When these characters are taken into account — and I hope to have 
proved in my »Echinoiden d. deutschen Südpolar-Expedition», that the reasons pro- 
duced by CLARK against using the pedicellariæ in the classification of Cidaridæ are 
irrelevant — it is evident that Austrocidaris is not so very nearly related to Cidaris 
( Dorocidaris ); the pedicellariæ, on the contrary, decidedly point towards Stereocidaris 
as the nearest relation. With Goniocidaris , to which genus most authors have re- 
ferred it, following AGASSIZ, it is not very closely related, as DÖDERLEIN (Jap. See- 
igeln p. 18) has sufficiently demonstrated. The deep median vertical furrow * — 
the character which has caused its reference to this genus — is certainly very dif- 
ferent (»durchaus nicht gleichwertig» DÖDERLEIN) from the depressions of the hori- 
* The alleged great variability of this furrow in canaliciilata : it being sometimes very distinct, some- 
times even totally absent, is due to the confusion of canaliciilata with other species, especially Eurocidaris 
nutrix. In true canaliciilata it scarcely ever disappears. It is true, DÖDERLEIN states (Japanischen Seeigel p. 
17) that in one of his specimens of canaliciilata »findet sich keine Spur einer solchen Furche, das Miliarfeld 
ist hier ganz flach und die Mittelnaht kaum zu erkennen». He further states that all his specimens proceed 
from Patagonia and the Magellan Strait, so that there should be no possibility of this specimen without 
the deep median line being E. nutrix. On my applying to Professor Döderlein concerning this matter, 
he most kindly sent me the specimen for examination, adding the information that it was bought from a 
dealer in Naturalia in Basel, who had got it from Prof. StüDER with other specimens of natural history 
from the »Gazelle». It was labelled »Gon. canaliculata, Ost-Patagonien». — The examination of this spe- 
cimen shows beyond doubt — in spite of the absence of the characteristic large globiferous pedicellariæ — 
that it is Eurocidaris nutrix; especially the apical system, so different from that of A. canaliculata , leaves 
no doubt of the identification. There must then evidently have been some confusion of the labels by the 
dealer — or by Studer. Of course, this specimen could not be taken as a proof of the occurrence of E. 
nutrix at Patagonia, against all other evidence. 
