by Frank E. Beddard. 143 
DorsaL Fin. 
In the fetus described by me in an earlier number of this journal, 
I found it difficult to differentiate the dorsal fin. This structure, 
however, is quite conspicuous in the two younger individuals whose 
characters I have more recently examined. It is very obvious in the 
larger of these two as a sharpish ridge 32 mm. in length, which begins 
and ends quite distinctly and hardly fades away into the general line 
of the back. It ends some way between the root of the penis and the 
umbilicus, nearer to the umbilicus, as can be ascertained on a lateral 
view, and as is just to be made out in the photograph on Plate X XII, 
Text-Fig. 10. 
YOUNGER Fatus. 
Tail showing dorsal surface. 
fig. 2 and (more clearly) in text-fig. 9, D.F. There is a slightly 
marked ridge, both in front and behind, which is smoother, not so 
sharp-edged to the touch and not so elevated. 
In the small fcetus the fin is also quite obvious, but not so clearly 
defined posteriorly. Its end is plain enough anteriorly and is seen to 
be at a point corresponding to about the middle of the penis on the 
ventral side; posteriorly it emerges into a sharp line which forms the 
back in this region and which suggests the conditions obtaining in 
other whales in the tail region. The fin itself and the back ridge near 
to it is crossed by a series of furrows quite narrow and at right angles 
