148 Anatomy of Sperm Whale Fetus. 
case of the left. The corresponding measurements made by Miss 
Lander give 12 mm. for the right limb and 11:9 for the left. There 
is thus an agreement as to the fact that the right limb is rather, but 
very slightly, the larger. In the larger foetus the greatest length is 
28-5 to 29-2 mm. and there is a cifference of only -7 mm. between the 
two sets of measurements. This only just affords a basis for differ- 
entiating the two limbs by their length. Indeed, the entire question 
does not seem to be capable of settlement by the facts at my disposal, 
especially when it is considered that, by an exact reliance upon the 
measurements, the older fcetus shows a faintly greater length of the 
lower margin of the fin as compared with the upper margin (measured 
in a straight line) as compared with the smaller feetus. The pro- 
portions of the paddle to the body length bear out what I mentioned 
in my earlier paper, viz., that while in the adult the fin is only one-tenth 
of the body length, the feetus has a relatively larger fin. I find that in 
the larger of the two described here the length is as much as 84 of the 
total length, much as in the older feetus first described by me. But in 
the youngest the fin is shorter, being 94. A longer series is clearly 
desirable. 
