Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/786

 straight narrow bone lying with one end in contact with the right coracoid, which may perhaps he a clavicle. A somewhat similar bone is also in contact with the left coracoid, but in this instance it has in some respects the character of a rib.

The humerus is one inch long, and is a slightly arched stout bone, with the extremities a little expanded ; the distal end, which is the wider of the two, is fully 1/4 inch across, while the most constricted part of the shaft is a little more than half that width. The proportional measurements of the humerus in P. Speneri differ considerably from the above. In that species this bone has the extremities extremely wide. One figured by von Meyer (tab. ix.), which is 2-1/2 inches long, has the shaft 3/8 of an inch thick, while the proximal extremity is a little less than 9/8 inch wide and the distal 9/8. In P. Huxleyi the proximal extremity is very little wider than the shaft, and the distal extremity is about twice as thick as the shaft. In P. Speneri the proximal and the distal extremities are three times the width of the shaft.

The radius and ulna are not by any means slender ; they are about 7/10 of an inch long, being considerably shorter than the humerus. The radius is not quite so stout as the ulna, and both exhibit a slight sigmoidal curve. The latter is 1/10 of an inch thick at the centre of the shaft, but is a little enlarged at the extremity.

The hand, including the wrist, is a little longer than the lower arm. There are two rows of carpals, of which, though disposed in nearly regular order, it is not easy to determine the precise number. There seems, however, to be three in the proximal row, and four or five in the distal, in all seven or eight. The metacarpals are long, being not much short of the length of the toes, of which there are five. The number of joints in each will have to be estimated rather than precisely determined ; for the extremities are considerably injured. The first is the shortest, and has apparently two phalanges ; the second has three ; the third has four, all of which are quite distinct ; the fourth, which, judging from the size of the phalanges, is the longest, has four, but as no trace of the claw is present, there has no doubt been an additional joint, bringing the number up to five, and if so, agreeing in this respect with P. Speneri.

The left fore limb is almost as perfect as the right, and lies stretched out nearly at right angles with the trunk, with the front aspect exposed ; the back of the right limb is uppermost. The proximal end lies upon the coracoid ; the distal extremity is separated by a short space from the radius and ulna, both of which are extended in parallel order to unite with the projecting wrist and hand. The two latter, however, are so much injured by the accumulation of galena that the parts are much obscured.

The chief bones of the left hinder limb, though dislocated, are lying close to the pelvic margin in nearly their natural sequence. The femur is as stoutly developed as the humerus ; it is 1-1/4 inch long, consequently a little more than 1/8 of an inch larger than the upper bone of the anterior limb; it is slightly bent, and has the extremities gradually but not excessively enlarged. The shaft is 1/8 of