1885.] Rudimentary Hind-limd of Megaptera longimana. 125 
thigh bone in this species had been discovered many years ago 
by the late Professor Reinhardt, of Copenhagen. The object ot 
the author's inquiry was to ascertain the precise anatomical rela- 
tions of this rudimentary structure, and if possible to throw 
some light on its meaning. For comparison the author exhibited 
to the section the rudimentary bony thigh bone, about the size of 
a hen’s egg, which he had found ina great fin-whale, the razor 
back (Balenoptera musculus), in 1871, and a series of specimens 
of the more developed thigh bone and cartilainous tibia, which 
he had dissected in the Greenland right whale (Ba/ena mysticetus), 
and his drawings of the ligaments and muscles connected with 
these parts in the right whale (Your. of Anat. and Phys., Jan. 7, 
1881). 
In this Megaptera he found the thigh bone to be entirely com- 
posed of cartilage, of a conical shape, the length five and a-half 
inches on the right side, four inches on the left. It was encased 
in a mass of fibrous tissue. This fibrous case was connected in- 
ternally to its fellow of the opposite side; superficially and on 
the outside to the posterior pelvic muscular mass; and anteriorly, 
passing from the thigh bone itself, was a special band appearing 
like a fibrous prolongation of the bone. The thigh bone rested 
loosely on the pelvic bone without articular surface, but was 
bound loosely to the latter by a strong posterior ligament, and by 
a weaker ligament in the position of the hip joint in the right 
whale. A muscle about the size and shape of a forefinger, within 
a ligamentous tube, connected the thigh bone backwards to the 
great interpelvic ligament. This was the only muscular struc- 
ture directly connected with the thigh bone. It would retract 
the bone. The fibrous connections of the bone were mainly 
adapted to resist outward and forward traction. 
The author said, that looking to all these facts, the conclu- 
sion to which we must come is, that the thigh bone in Megap- 
tera is a rudimentary structure, a vestige of a more complete 
limb possessed by some ancestral form from which the Megap- 
tera is descended. 
The skeleton of this Megaptera he hoped ‘would be ready to 
be inspected by the members of the British Association at the 
meeting in Aberdeen in September, 1885. 
