Notocrinus virilis n. g., n. sp., 
a new viviparous Crinoid from the Antarctic Sea. 
Preliminary notice. 
By 
Dr. Th. Mortensen. 
Up to the beginning of the present century not a single vivi- 
Parous Crinoid was known, a rather curious fact, considering the 
fairly large number of viviparous forms known in the other classes 
of Echinoderms. It roused, therefore, a good deal of interest, when 
in 1905 Dr, K. A. Andersson in his paper ,Brutpflege bei Ante- 
don hirsuta Carpenter") made known the first remarkable case of 
a viviparous Crinoid. 
Dr. K. A. Andersson did not give any detailed account of the 
development of his »Antedon hirsuta", and as he has informed 
me that he does not expect to get the opportunity to do so, I 
applied to Professor O. Nordenskjåld for permission to work 
Out the development of this species, in order that I might include 
the report on it in a memoir, now under preparation, on the devel- 
Opment of some Crinoids, based on material collected during a voyage 
in the Pacific and the West Indies in 1914—16. Professor Norden- 
Skjåld not only readily granted my wish, but he also ordered the 
Whole collection of Crinoids made by the Swedish Antarctic Ex- 
Pedition sent to me, thinking that there might be something more 
in it to interest me. And so it turned out, indeed, even far beyond 
€Xxpectation. I beg herewith to tender my sincere thanks to Pro- 
fessor Nordenskjåld. 
The collection contains, after a preliminary examination, only 
4 species, viz. besides the » Anledon hirsuta" of Dr. K.A. Anders- 
") Wissensch. Ergebnisse d. Schwedischen Siidpolar-Expedition. Bd. 5. 
