248 MR. R. COLLETT ON BAL-liNOPTKRA BOREAl-IS. [Feb. 2, 



III. Measurements, 



Most of the examples caught were between 40 and 50 feet 

 in length. The usual length was 44-45 feet or thereabouts. The 

 largest specimens measured 52 feet' (16*3 metres). The 6 specimens 

 which I examined thoroughly were 43 to 49| feet in length (see 

 p. 247). The last of these (a male) was considered to be one of the 

 largest caught ; so that it may be laid down as a rule that they 

 rarely exceed 50 feet (15'6 metres). 



The smallest specimens this summer that I know of were 35-37 

 feet, but these were exceptional. A single specimen was caught in 

 July at Mehavn (by Foyn), the length of which was said at the place 

 to be 32| feet (10-1 metres). 



Both sexes seem to attain about the same size ; the largest 

 female specimen that I examined was 47 feet long (14'7 metres). 

 One of the managers stated that if there were any difference, the 

 female was the largest and fattest, at any rate during the whaling- 

 season. 



The size appeared the same throughout the season, and it was 

 remarkable to notice how uniform it was, and how evidently the 

 whales were all of about the same age. 



IV. Structure of the Body. 



The Structure of the body seems to correspond with that of B. sib- 

 baldi, which it on the whole resembles in its mode of living. 



The body is highest across the middle of the flippers, where, in 

 the case of the living animal, the height is to the total length about 

 as 1 to 5^ (as in the case of B. sibbaldi). In the stranded animal, 

 when the belly is compressed by the ground, the proportion is as 

 about 1 to 6. The height of the body is thus not so great as in 

 B. rostrata, which is at that point relatively the largest of all the 

 four species. 



The form of the hinder part of the body does not differ essentially 

 from that of the otlier species. Immediately under the dorsal fin the 

 height is one eighth of the total length, and halfway between the dorsal 

 fin and the root of the tail one tenth. From these proportions it 

 will be seen that in this respect it also corresjionds most nearly with 

 B. sibbaldi, and is neither of the exceedingly slender " emaciated " 

 form of B. musculus, nor of the comparatively stout form of B. 

 rostrata. 



The breadth of the body can only be given approximately, and 

 would seem across the flippers to be not very diOerent from the 

 height. From the vent to the root of the tail the body is strongly 

 compressed, and the caudal part forms, as in the other species of 

 Balcenoptera, a thin ridge above and below, which is particularly 

 sharp along the dorsal line. The breadth at tlie root of the tail at 



^ [About 54 feet English, and so with the other measurements; the Norwegian 

 foot almost = 12| inches English. — ^A. H. C] 



