| OCR Text |
Show 1889.] ANATOMY OF BURMEISTER's CARIAMA. 597 In Chunga (fig. 3, p. 598) there are differences in all the points just enumerated. The first rib is very rudimentary ; only ribs 4, 5, and 6 (i. e. one less than in Cariama) are furnished with uncinate processes, which are straight, directed upwards and backwards, and not curved ; the sternal half of the first complete rib is slender. There is a rudimentary 8th rib on each side; on the left side of the body it consists of a curved piece continuous below with the sternal portion of the 7th rib ; on the right side a shorter piece lies along the posterior border of the sternal half but not fused with it ; there is also a small rudiment of a vertebral rib attached to the transverse process of the 8 th dorsal vertebra. The proportion between the length (from point to point) of the lateral margin of the sternum and the length of the space occupied by the attachment of the sternal ribs is : - in Cariama, 2*4 : 1*35, in Chunga, 2*5 : 1*15, showing that in the latter genus the attachments of the ribs are more crowded together than in the former; at the same time the first sternal rib is attached much nearer to the anterior lateral process of the sternum in Chunga than it is in Cariama. The sternal rostrum is more developed in the latter type, and there is a difference in the shape of the sterna on a lateral view which will be more easily appreciated by an inspection of the accompanying woodcuts (figs. 3, 4) than by a description. In the pelvis (see figs. 5, 6, pp. 600, 601) the chief differences are, firstly, that the ilia extend rather further forwards in Cariama, very nearly reaching the last rib but one; in Chunga the anterior extremities of the ilia only just get beyond the seventh rib. Secondly, the line of junction of the transverse processes of the lumbar vertebrse with the border of the first acetabular ilium forms a straight line ; in Chunga the corresponding line is curved. The breadth of the pelvis is greater in Chunga, the proportion between length and breadth in the two types being as follows :- Length of pelvis. Breadth. in. in. Chunga .... 2*95 1*6 Cariama.... 3*25 1*6 These measurements of breadth are taken from the extremities of the post-trochanteric processes, which are well marked in both these birds, but perhaps if anything rather more marked in Chunga. If these measurements had been made between the antitrochanteric processes, the contrast between the two types in the proportions between length and breadth of the pelvis would have been greater than is indicated in the above table ; these processes are more strongly developed and project further out in Chunga than they do in Cariama. |
