124 
stomach must be stopped during the time of the hatching; no rests 
of food were found in the stomach of any specimen containing 
young. It may be expected that this can be definitely settled by 
a careful histological study of specimens preserved for such pur¬ 
pose. 
I cannot enter here on the description of the embryological devel- 
opment of this species, but must content myself with giving a pair 
of figures of the embryos ( Fig. 2), from which appears that their 
shape is very similar to that of the embryos of Asterias Mulleri. 
Probably they leave the stomach of the mother by the time they 
have reached the stage shown in the right figure, no further ad- 
vanced stages having been observed. 
The eggs are large (ca. 1 mm). It is important to notice that 
all the eggs or embryos found in a specimen are of the same 
size; accordingly they must be emptied from the ovary all at the 
same time, not at different times, as would appear to be the case 
in Asterias Miilleri. 
The complete study of the embryonic development requires a 
large specially preserved material. I hope to get an opportunity 
of going to Greenland in order to collect such material and, in 
the same time, to make observations on the living specimens regard- 
ing this very remarkable breeding habit, hitherto recorded in only 
one other Echinoderm, namely Stichaster nutrix Studer. 
In his paper on the Echinoderms of East Greenland, Dr. Th. 
Mortensen 1 ) expresses the opinion that Asterias grønlandica can¬ 
not really be distinguished from Asterias Mulleri Sars, and later 
authors have in general agreed with him in this regard. The faet 
here disclosed that it hatches its young in its stomach, while — 
according to M. Sars 2 ) — Asterias Miilleri hatches them only in 
the cavity made by the raised arms. would seem to show that 
Asterias grønlandica must, however, be a distinet species. I shall 
not enter on this question at the present occasion. Renewed ob¬ 
servations on the breeding habits of Asterias Miilleri would, how¬ 
ever, also be very desirable. 
') Dr. Th. Mortensen: Echinoderms from East Greenland. Meddelelser 
fra Grønland. Vol. XXIX. Copenhagen. 1903. pag. 68. 
2 ) Op. cit. pag. 58. 
