ON BELMULLET WHALING STATION, 157 
Larger forms are also met with, having a much lighter coloration 
on the dorsal surface, often with a yellowish tinge. These are not so 
cunning in their habits, and are more easily caught, being more like 
Sperm whales (Physeter macrocephalus, L.) in their slower movements. 
The smaller form appears to be the ‘ Herring whale ’ of the whalers, 
and to correspond to the smaller black (?) variety of Haldane. Lydekker 
concludes that the dark Rorquals are probably the oldest, and that they 
feed on herrings and pilchards. It must be noted, however, that he 
takes a variation in colour on the under-side of the tail for the differing 
colour character. Also one would hardly expect the oldest animals to 
be the smallest, although Haldane’s darkest variety is stated to be the 
smallest. 
Evidently this question of varieties is not settled, and further reliable 
information must be obtained. It seems to be certain that there are 
variations in colour, habits, and food, but whether the varieties can be 
given even sub-specific rank remains doubtful. Although a species may 
be cosmopolitan, it does not necessarily follow that the individuals range 
over the whole world, and there seems to be no reason why more or less 
localised races should not arise.!? In the present state of our know- 
ledge the facts certainly point to the existence of one or two of these 
races in the case of Balenoptera musculus. (L.), differing in several 
points from the type of the species. 
6. Opinions appear to differ with regard to the proportion in which 
the sexes of B. musculus occur. Thus Haldane™ states that the cows 
are less numerous than the bulls. Southwell?” says that the sexes 
occur in about equal proportions, while True concludes !* that the 
females predominate. 
The actual proportion in which the sexes occur certainly varies; 
thus, in the season of 1906 the Shetland whalers actually found the cows 
to be more numerous than the bulls,}® although in other seasons the 
reverse had obtained. If reference be made to Table II. in this report 
it will be seen that the proportions are twenty-five males to twenty-one 
females. From Table XI., however, it appears that the female and 
male foetuses occurred in the proportion of five to two. Although the 
number of foetuses is not very large, this would appear to indicate that 
the usual smaller number of large females captured is due probably to 
their greater timidity. If a large number of foetuses be used for this 
calculation it is found that the average shows that the two sexes occur 
in equal proportions,*° so that the greater timidity of the cow appears 
to be the only explanation of the relatively smaller numbers caught in 
European waters. 
With regard to B. sibbaldii all the adults I examined were females, 
but as the number amounted only to four, no conclusions could be 
drawn as to the proportions of the sexes. 
** Vide True, Smithsonian Contrib. to Knowledge, vol. xxxiii., 1904, Intro- 
duction, &c. 
*© Haldane, Ann. Scot. Nat. Hist., April 1905, also April 1908. 
“ Southwell, Ann. Mag. Nat. Hist., vol. xvi., October 1905. 
8 True, op. cit., p. 112. 
Haldane, Ann. Scot. Nat. Hist., January 1907. 
*° Haldane, Ann. Scot. Nat. Hist., April 1908. 
