144 REPORTS ON THE STATE OF SCIENCE.—1914. 
account, because very few of this species have been seen in the pregnant 
condition, the six foetuses which we saw have the following dimensions : 
Ft. in. 
July 15 15 0 
Aug. 7 Sv 
eee aC 4. 40 
acl 7 10 
Sept. 4 3 11 
9 &4 = 
Burfield’s table of foetuses observed in 1911 is as follows :— 
Ft. in. 
July 12 8 ll 
» 16 4 11 
» 20 8 5 
» 24 6 0 
Aug. 7 5 6 
sr L 9° 0 
Sept. 10 S0 
» 18 9° 33 
The young whale appears to be about 20 ft. long when born. 
If the size of the fcetus is proportional to the length of gestation 
which has elapsed since pairing until the time when the fcetus is 
measured, and if the period of gestation is ten months,’® then the 
foetuses found must have been the result of pairings at approximately 
the times given opposite each in the table which follows :— 
Ft. in. 
July 15 . 15 0 age 74 months, pairing took place December—January. 
At lipase) Ole san 55 5 = April (beginning). 
» 7 4 0) '),-2 » 9 » June. 
en 7 10 S74 a 3 sf April (end). 
Sept. 4 Sl. Si2 $3 M » duly (beginning). 
2 9 4 ” 5 ” ” ” May. 
Pursuing the same idea with the 1911 fcetuses, we have :— 
It. in. 
July 12 8 11 age 4} months, pairing took place March (beginning). 
5, 16 4 AL. ys 2k a5 55 BS May (beginning). 
pees) 8 5 ,, 4% A ¥ at March (beginning). 
ae A Ge Ores ss 3 mr April (end). 
Aug. 7 DRO ats bs 5 May. 
ape! OPO as BD fs # = March-April. 
Sept. 10 95°20 5 2 58 “s re May (beginning). 
ls OS to sae #5 =p 6 May. 
These times can only be regarded as approximate, even if the 
premises upon which they are based be correct. It is, howeyer, 
suggested by this table that pairing may take place at any time 
between the end of December (the first in the 1913 series) and the 
beginning of July (fifth in the 1913 table), at intervals of roughly 
two months. This would indicate that the Balenopterids are, at any 
rate, polycestrous, and in season in December (February ?), April, and 
June. All females would not be fit for breeding actually simultane- 
ously, but the precise time would vary for different individuals, and 
*% Burfield, op. cit., p. 155. 
