Bd. V: 6) 
THE FISHES OF THE SWEDISH SOUTH POLAR EXPEDITION. 
2 9 
of head, reaching beyond origin of anal, with blunt tips. Caudal truncate. Caudal 
peduncle a little shorter than deep. Scales thin, ctenoid, comparatively large on 
posterior part of the body. Upper lateral line with 25 — 30 tubular scales, lower not 
conspicuously developed.* In a specimen with 25 tubular scales in upper lateral line 
about 20 more scales can be counted from posterior end of the lateral line to caudal 
fin. The total number in a longitudinal series of scales above the lateral line might 
be approximately about 60. 
The length of the three specimens is from 39 to 45 mm. without caudal fin. 
The number of rays in dorsal and anal fins of this fish resemble the correspond- 
ing ones of N. longipes. The ventral fins appear to be even longer than in the 
latter species. The general appearance of these two fishes is, however, quite diffe- 
rent. N. longipes is less compressed and its depth of body is, at least in young 
specimens, smaller when compared with the total length than in the fish named N. 
dubia. The latter has also much smaller eyes, the diameter of which is shorter than 
snout (in N. longipes longer). The scales of the head are much better developed 
in N. longipes and even in small specimens seen all over the whole interorbital re- 
gion. This comparison between specimens of similar size proves the diversity of 
the two fishes mentioned. From N. nicolai the present fish differs through its scaly 
occiput, and the same character prohibits its referring to N. coriiceps and N cyaneo- 
brancha, the two latter also having a much broader and more depressed head of 
entirely different shape. N. elegans has a narrower interorbital region, and the eyes 
longer than the snout. N. marionensis has a much narrower interorbital space with 
better developed scales and less compressed body and head, different number of fin 
rays etc. N. mizops has a narrower interorbital space, still longer ventrals, deeper 
caudal peduncle, larger eyes etc. N. sima has different number of fin rays, better 
developed scales on the head, larger eyes etc. N. tesselata has much shorter vent- 
rals, larger eyes, more scaly head etc. 
The differences between the 3 specimens of Notothenia from Boiler Harbour and 
other species of Notothenia are thus quite apparent without the necessity of extending the 
comparison to the species with extremely broad or extremely narrow interorbital space. 
A few comparative measurements of N. dubia are recorded below. 
Total length without caudal in mm 43,5 
Length of head in % of total length without caudal 27,8 
» » snout » » » s » » » 9,2 
Diameter of eye » s » » » » » 7,1 
Interorbital width » » » » » * s 14,, 
Length of ventral fin » » » » » » > 23,9 
Depth of caudal peduncle » » » » » 1 » 7,4 
* The line with a corresponding situation in the figure (fig. 9 PI. Ill) represents only the very con- 
spicuous limit between the upper and lower portions of the lateral muscles. 
