182 REPORTS ON THE STATE OF SCIENCE.—1912. 
Taste XII.—Balenoptera musculus (L.), Foetuses. 
| cot Seabees Sete tay Ieee | No, 18 | No.25 | No.37 | No. 51 
| F) Ee one 3 
Ft, in. | Ft. in. | Ft. in. | Ft. in. Ft. in.) Ft. in 
Total length. . .| 8 11 | 4 11 85 6 0/9 0 9 38 
Tip of snout to centre of | 
eye cA. ti cere Jagit bowpylet ema! pel) yo joe ea yrigge iat itiy 
Tip of snout to centre of | | | 
blowhole . . «| 1 4) 84, 1 4 | 103, 1 4); 1~= «44 
Tip of snout to posterior | 
insertion of pectoral | | 
fini we el] PORE UBF CZ OP 2 Sse oS AUG INg tee 
Tip of snout to posterior | 
insertion of dorsal fin; 6 10 | 3 8$| 6 23} 4 5,6 9/17 #O 
Eyetoear . . . 9} 3 6 72 | 6 meet 
Notch of flukes toanus, 2 9/1 6/;2 6/1 98 2 7) 2 «10 
Notch of flukes to um- | | 
bilicus {i evBroe Bry, thesis shill 26.81 | 8. cos) Ay s 
Length of pectoral fin | | | 
(tip to anterior inser- | 
tion) *..S8t. 20.5 Mig. te 3 MBL ehay 9 [4 gay ocd 
Length of pectoral fin | 
(tip to posterior in- 
EGON) core ee ed 5} 9} 6 | 1 0} 11 
Greatest breadth of | 
pectoral fin. . . 4 14 3h | 2} | 3} | 4 
Vertical height of dorsal | 
Ie ee Sere 3h ea 4 2. 35) 3} 
Flukes (tip to tip)  ./| 1 7 | Wy — en Ld 8 
Number of breast folds | 
between pecteral fins | 70 . 60 | 86 64 5 — 60 
B. Colour—In all the foetuses the upper part of the body was 
similar to that of the adult, but the under-side was a deep-pink colour. 
This appears to be due to an effusion of blood into the skin, and has 
been noted in the case of Mesoplodon bidens by Southwell and 
Harmer,*® 
C. Body Form.—This in all the foetuses was the same as that of the 
adult. Thus, the smallest foetus examined, which was about one- 
quarter the average size at the end of gestjation, was entirely like the 
adult in form, except that it was less robust. ‘The tail-flukes in all the 
foetuses were markedly bent towards the ventral side of the animal, so 
as to present a very concave ventral surface. In obtaining the distance 
between the tips of the flukes the latter were stretched apart as far as 
they would go, but they could not be stretched out as flat as they appear 
in the adult. 
D. Throat Furrows.—These were as fully formed as in the adult. 
The average from the numbers in five individuals was sixty-eight, a 
number closely agreeing with that obtained from the adults. 
E. Whalebone.—This was not developed sufficiently to show 
through the gum in any of the foetuses, but if a thin strip were taken 
from the inner edges of the upper jaw the rudiments of the plates could 
be seen. 
“* T. Southwell and §. F. Harmer, Ann. and Mag. Nat. Hist., 6, vol. xi., 
April 1893. 
