49 
inity, sweep the bottom. The occurrence in the inlets of the west 
coast of Greenland demonstrates, that the species may bear a low, 
even negative temperåture, but avoids water of low salinity. 
Accordingly Ritter-Zåhony's characterization of the occur- 
rence of the species as only dependent on the temperature not 
rising above a certain maximal degree, cannot be maintained. It 
is true, no doubt, that the complete absence from the upper 
Strata of the tropical and subtropical seas is due to the high temp- 
erature, but the experiences drawn from the collections of the 
"Tjalfe" expedition prove, that the salinity has also a considerable 
importance, as far as it must not come very much below 34 9%/00. 
— The depth of the bottom is, undoubtedly, also a factor of im- 
portance. The predominant number of localities, where E. hamata 
has been found within the north-atlantic region, are situated out- 
Side the 600 m line, and only in very few cases the species has 
been found inside the 200 m line. 
The question of the conditions of life of Eukrohnia hamata 
is, accordingly, really rather complicated. 
The ripe sperm has a brownish-reddish colour, while the unripe 
testes are pale-yellow — At about the same time as the male 
products reach maturity, the receptacula seminis seem to become 
able to receive sperm. I have seen specimens, in which the re- 
Ceptacula seminis have been filled by sperm (the eggs still being 
Very small) at the same time as the tail has contained mature 
Sperm, Ovaries, the eggs of which have commenced to mature, are 
Only seen in such specimens the sperm of which has been nearly 
Or completely evacuated. When the oviduct is filled with ripe eggs, 
every trace of sperm has disappeared from the. coelom of the tail. 
Eukrohnia hamata is, accordingly, strongly protandric. But, 
aS we have seen, the receptacula seminis are able to receive sperm 
at the same time as the animal spawns its own sperm; thus self- 
fertilization does not seem to bee excluded. 
We may group the specimens according to the state of maturity 
in the following manner: 
Group I. Both kinds of sexual products immature. To this 
group I have also referred specimens in which 
Vidensk. Medd. fra Dansk naturh. Foren. Bd. 69. 4 
