31 
THE GEOLOOrST. 
or three digits in tlie hand. There was no trace of the fifth digit of the 
winged reptile. Of the pelvis, a bone on the left side was preserved, bear- 
ing a resemblance to the iliac bone of a bird, and with a sinuous border ; 
its exposed surface was smooth and polished, and 7 lines broad. The an- 
tero-interior surface of the ilium and the coalesced ischium terminate ab- 
ruptly and obtusely, as in a young bird. The ischium, behind the aceta- 
bulum, shows a vacuity between itself and the pubis, the obturator fora- 
men being as large as in birds. In the Pterodactyle the ilium is shorter, 
the ischium being subtriangular, joining with the ilium. The sacrum was 
a confused mass of vertebrje, in which six or seven short transverse pro- 
cesses can be seen. The conditions under which the skeleton was found 
reminded Professor Owen of the carcass of a gull, which, after having been 
a prey to some carnivore, which had removed all the soft parts, and per- 
haps the head, had left nothing but the bony legs, and the indigestible quill- 
feathers. The tarso-metatarsal, at its distal end, exliibited a trifid, tro- 
chlear, articular surface, supporting three toes. The shaft of the femur was 
long and thin, while a procnemial ridge was present on the tibia. The size of 
the procnemial ridge is variable in birds ; in Archaeopteryx it was as large as 
in Falco irivircjatus and in most Volitores. The thigh was longer than in 
the majority of birds. The proportions of the toes accord with the inses- 
sorial, and not with the scansorial type of foot. Few of the bones are in 
a condition to permit minute comparison of their texture. The osseous 
remains having been exposed to a disintegrating action by which the 
phosphate had been converted into carbonate of lime, and in the interior 
of the bones crystallized spar has been deposited. Each vertebra of the 
tail supports a pair of plumes. The fossil differed from all known existing 
birds in having a tail composed of twenty vertebree. But the tail is essen- 
tially a variable cliaracter ; there are long-tailed bats and short-tailed bats, 
long-tailed rodents and short-tailed rodents, long-tailed Pterodactyles and 
short-tailed Pterodactyles. It is now manifest that there existed, at the 
period of the deposition of the Oxfordian strata, a bird exhibiting the persist- 
ent embryonal or generalized character of the tail, as opposed to the special- 
ized condition of the tails of existing birds, in which the terminal vertebrae 
have coalesced. All embryo birds exhibit the caudals distinct, the greatest 
number of separate caudals being exemplified by the ostrich. The develop- 
mental process undergone by the bird is similar in nature to that through 
which the fish passes in its transition from the heterocercal stage, through 
which it usually passes, to the homocercal. The probability of the presence 
of a single unguiculate digit, as in the wings of Pteropus, would, if demon- 
strated, exhibit a similar retention of an embryonal and transitory character. 
The Archseopteryx was unequivocally a bird ; and, by the law of correlation, 
we might infer that it was destitute of fleshy lips, that its feathers were 
preened by a horny edentulous beak, and that the shape of the breast-bone 
was such as was possessed by animals capable of flight. The President 
moved a vote of tlianks ; and, calling for remarks, the Duke of Argyll 
hoped that Mr. Gould would offer some opinion on the fossil. Mr. Gould, 
r.E.S., considered that the remains indicated a terrestrial form of bird, 
with wing feathers not adapted for flight, as in the Apteryx, or in the 
black rail of New Zealand. Had the hind foot alone been shown to any 
ornithologist, he would have been entitled to infer that it was a bird — a 
fact which Mr. Gould had doubted up to the previous day, but which he 
now felt constrained to admit. Dr. Carpenter, F.R.S., coincided in Pro- 
fessor Owen's remarks respecting the more generalized vertebrate type of 
the specimen, and remarked on the futility of negative evidence in geolo- 
gical discussion. Professor Owen pointed out that the shape of the pec- 
