8 LÖNNBERG, FISHES FROM SPITZBERGEN AND KING CHARLES LAND. 
large size, the diameter being about 2 mm.» And he adds 
that these ova were »apparently mature». Under such circum- 
stances the present writer was much astonished to find, when 
opening the abdominal cavity of the last caught of the above 
mentioned specimens, that it was not yet spent. It was a 
female of exactly the same length as the specimen referred 
to by CoLLETT (total length 69 mm.) and it was obtained be- 
tween Beeren HEiland and Norway (conf. above) the 4th of 
September. Its abdomen was much distended by the ovaries 
which contained very large ova. These measured fully 4 mm. 
in diameter, but were of course few in number, 7 in the right 
and 8 in the left ovary. This large size and small number 
of the ova seems strange when compared with the conditions 
in related forms. It is possible that the eggs are gradually 
developed and laid in sets of 8 to 10 (or so about) each time 
and that the ovaries of the specimen now dissected just con- 
tained the last set. For so many as 32 ova as CoLLETT 
counted in each ovary cannot have space to obtain full size 
at the same time, and it is not probable that the size and 
number of ova is subjected to variation to such extent as 
the investigation of CoLLEtt compared with the present seems 
to indicate, if CoLLEtt's specimen should have been ready to 
spawn. The specimens caught ?5/s off Grey Hook (North 
Spitzbergen) were not mature so that from their condition 
no information could be obtained. 
The situs viscerum is, on the whole, like that in other 
Cottide, but there are only 3 appendices pylorice. The peri- 
toneum is blackish in its upper and anterior parts. 
For this, and the following species, SMITT has in the men- 
tioned work given some comparative measurements intended 
to show that the relation between the two species of Centri- 
dermichthys is similar to that between the species of Gymno- 
canthus. The comparative length of the head in the two 
species of Centridermichthys does not however show such pro- 
nounced difference as in the species of Gymnocanthus. In 
four specimens of C. uncinatus measuring resp. 85, 69, 61 and 
44 mm, the length of the head was resp. 31,7, 33,3, 31,1 and 
34,0 2 of the total length. In three male OC. hamatus mea- 
suring resp. 65, 63 and 62 mm. the same percentage was resp. 
30,0, 30,1 and 30,6 2, in three females of the same species 
measuring resp. 77, 75 and 69 mm. the same percentage was 
