704. MR. W. H. FLOWER ON PHYSALUS ANTIQUORUM. [Nov. 28, 
with the surrounding parts, had, before I arrived on the spot on 
Monday morning, been already severed from their connexion with 
the spinal column, and had to be sought for among a mass of most 
uninyiting-looking carrion thrown upon the beach. Dr. Murie kindly 
assisted at this part of the examination; and we were not long in 
discovering their situation and in determining one of the most im- 
portant points in the anatomy of this animal that has hitherto re- 
mained unsolved. 
Many years ago Reinhardt discovered that, besides the ordinary 
elongated bone found on each side of the pelvis in all Cetacea, and 
to which the corpus cavernosum of the penis is attached, there is 
also, in the Greenland Whale (Balena mysticetus), a second, smaller, 
more rounded bone, attached by ligamentous fibres to the outer side 
of the former. More recently it has been proved (Eschr. & Rein- 
hardt ‘On the Greenland Whale’) that, at least in some, if not all 
specimens of the same animal, a third, still smaller bone is present, 
attached to the distal end of the second. In the Megapéera there is 
a second bone on each side, though smaller and less definitely shaped 
than in Balena; but hitherto no trace of this bone has ever been 
found in any of the true Fin- Whales, although in one species at least 
( Balenoptera rostrata) it was carefully searched for by Eschricht. 
‘This distinguished cetologist was at first inclined to regard these ac- 
cessory bones, especially as then only the one pair were known, as 
having their nearest analogy in the marsupial bones of the Marsu- 
pialia; but in his more recent work, written in conjunction with 
Reinhardt, they are regarded (and, I think, with much reason) as the 
homologues of the posterior extremities of the ordinary Mammalia 
—the first accessory bone representing the femur, and the second 
(found only in the Balena mysticetus) the tibia. 
On searching in the neighbourhood of the larger bone, I found, 
not indeed another bone, but a distinct nodule of cartilage, of a 
slightly compressed irregularly oval form, 13 inch long and ? inch 
across, enveloped in a fibrous capsule, and attached by fibrous tissue, 
at the distance of about 3 inch, to the outer side of the main bone, 
al =F 
ff 
rather in front of the middle. Both of the larger bones had this 
cartilaginous appendage, which I can scarcely doubt is the rudimen- 
tary representative of the hind leg of this colossal mammal. 
The two bones forming the pelvis resembled each other very 
closely both in size and form, and were precisely similar in general 
