54 
EINAR LÖNNBERG, 
(Schwed. Siidpolar-Exp. 
A few conclusions may be drawn from these facts recorded above. It is evident 
that the members of the family Nototheniidæ do not spawn all at the same time of 
the year and this is not even the case with the members of the genus Notothenia 
itself. Some of the latter seem to spawn in the antarctic spring or, perhaps, already 
in the later part of the winter (N. sima , brevipes , macrocephala , and in. marmor ata ), 
others in the antarctic autumn or beginning of the winter (N. mizops nudifrons , 
and larseni). A third category which in the winter shows genital organs in a mini- 
mum of development (as for instance N. coriiceps and gibberifrons) most probably 
spawn in the summer. Trematomus hansoni georgiamis seems to belong to the same 
category as the first group of Notothenias. The same and all the species of Noto- 
thenia , in which the present author has found ovaries in an advanced state of deve- 
lopment appear to have comparatively small eggs, about I to I r / 2 mm., in the ovary. 
The more specialised members of the family, on the other hand, as Artedidraco 
mints and Chcenichthys gunnari have larger eggs, 2V2 — 4 mm. Thus, the more 
primitive species have smaller, the more specialised larger eggs. It is only a pro- 
duct of a consequent development in the same direction when finally the highly 
specialised deep sea fish Racovitzaia has acquired a “poche incubatrice” as DOLLO 
recently has described in his interesting memoir repeatedly quoted. That the eggs 
when large are demersal, and not pelagic is certain, but whether the small eggs of 
the more generalised types ( Notothenia , Trematomus) are demersal or not, cannot 
theoretically be fully decided on the base of the relationship as the experience has 
taught us that of two nearly allied fishes the one may have pelagic (f. i. Clupea 
sprattus ) and the other demersal eggs (f. i. C. harengus). The size of the eggs 
cannot with certainty help us to decide this question, when the diameter is less than 
I Va mm., although it appears probable that eggs which have attained that size al- 
ready in the ovary may be demersal. There are, however, other circumstances 
which speak more strongly for the demersal nature of the eggs of Notothenia and 
Trematomus, viz. the variable spawning time compared with the climatic conditions. 
The variable spawning time seems to indicate that one time of the year should be 
as favourable as the other for the development of eggs. This might, within certain 
limits, be true for demersal eggs on the bottom of the sea, but not for pelagic eggs 
within the true Antarctic region, where the sea, to a great extent, during the winter 
is covered with thick ice. Therefore, when we have seen that such species as Noto- 
thenia mizops nudifrons, and N. larseni, which also are found within the true Ant- 
arctic region, are ready to spawn in the beginning of the antarctic winter, it might, 
without too great a danger of making a mistake, be concluded that these fishes have 
demersal eggs. A similar judgement may also be passed about Trematomus han- 
soni ( georgianus ). 
