
M 10 Brirish CoLuMBIA. 1922, ; 



leg before it was cleaned of the blubber and flesh was, as before stated, about 4 feet 2 inches 
from the body.” 
_ After studying the material and discussing it with various scientists, IT haye come to the 
conclusion that the protrusions actually do represent vestigal hind limbs and show a remarkable 
reversion to the primitive quadripedal condition. 
IT am well aware that zoologists are inclined to accept reported instances of reversion with 
extreme reluctance, and that at first sight the tendency will be to consider this a teratological 
ease of no reversionary significance, but the evidence is so strong that I cannot interpret it 
that way. 
Mr. Ruck reports that the total length of the leg ‘“‘ before it was cleaned of the blubber and 
flesh”? was about 4 feet 2 imches. The skeletal remains in my possession consist of two bones 
and two heavy eartilages. When placed in position as in Fig. 2, the total length is 31 inches. 
Femur.—The larger bone is deeply concave proximally and to it is attached a massive 
cartilage (Fig. 8) which in its present shrunken condition is 514 inches in length and 1% inches 
wide. I estimate that this cartilage was at least 15 inches long and 3 inches wide when fresh. 
I believe that this cartilage represents the femur. It probably lay entirely within the body, its 
proximal end being attached to the pelvic vestiges. Such a massive cartilage must necessarily 
have had a firm support and leads me to believe that the pelvic elements in this individual 
were of extraordinary size. The pelvic bones as usually present in the Megaptera are slender 
ossifieations about 6 or § inches in length and would not furnish a firm enough base for the 
attachment of a cartilage which in its fresh condition was as large as a man’s wrist. 
Since the photograph of the limbs in sitw shows that they were directly below the usual 
location of the pelvie vestiges, and since there are no other “ floating” bones near this region, 
the conclusion that they were attached to the pelvic elements is entirely justifiable. 
Tibia.—The larger of the two bones I identify as the tibia (Fig. 3). It is 14% inches in 
greatest length, is well developed, and has a hard smooth outer surface. At the proximal end 
its greatest width is 3% inches, it narrows gradually for three-fourths of its length, and then 
suddenly expands at the distal extremity, where it is 2% inches wide. 
Tarsus.—The distal end of the tibia is convex and gives attachment to a cartilage which in 
its shrunken state is 4% inches long and 1% inches wide (Fig. 4). This cartilage, I believe, 
represents the tarsus. That it presents no ossifications is by no means surprising, as the carpal 
vones in the fore limbs of cetaceans are sometimes entirely absent and often in a more or less 
rudimentary condition. Mr. Ruck says: ‘The two bones of the leg which you have are con- 
nected by cartilage which I was informed had shrunk about 10 inches and possibly more by 
this time.” This would give the tarsal cartilage a length of nearly 15 inches. . 
Metatarsal.—The distal element in the leg is a hard, well-developed bone which I identify 
as a metatarsal (Fig. 4). It has the characteristic shape of the metacarpals in the fore limbs 
of cetaceans, except that it is more slender. It is 64% inches long, 1% inches wide proximally, 
and 1% inches in distal width; its least width is ”/,, inch. To the distal end of the metatarsal 
is attached a heavy cartilage, of which only % inch remains intact. This cartilage probably 
formed the extremity of the limb skeleton. 
External Appearance of the Limb.—In reference to the limb as it appeared in the fresh 
condition, Mr. Ruck says that the end terminated in a “ kind of round knob like a man’s clenched 
fist,’ that the total length was about 4 feet 2 inches, and that it was covered with blubber about 
VY% inch thick. I infer from Mr. Ruck’s description that the connective tissue and blubber were 
essentially the same as in the flipper, or fore limb, of cetaceans. The photograph of the limb 
in situ (Fig. 1) shows that there are two prominent, truncated tuberosities on the distal half. 
The proximal “bunch” evidently indicates the distal end of the tibia and the other is at the 
extremity of the metatarsal. These tuberosities may very properly be homologized with those 
on the outer, or anterior, edge of the flipper in the Megaptera, which indicate the extremities of 
the radius and the second digit. This is, I believe, a point which has considerable significance. 
Since the stalk-iike cartilaginous femur probably lay entirely within the body and the 
remainder of the limb entirely outside, there was undoubtedly a certain flexibility at the point 
of junction with the body. 
In a paper entitled “ Untersuchungen an walen,”’* Professor W. Ktikenthal has described 
external rudimentary hind limbs in three early embryos of Megaptera. These appear as two 
* Jenaische Zeitschrift fiir Naturwissenchaft, Ll, 1914, pages 49-52. 



