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Show 1868.] PROF. HUXLEY ON THE ALECTOROMORPHAE. 299 In the Alectoropodes- 1. The osseous junction of the lophosteon and metosteon is narrow, the inner notch being always more than half as long as the sternum (fig. 2, p. 297). 2. The costal processes of the pleurostea (cp, fig. 2) are more prolonged and more nearly parallel with the axis of the sternum than in the preceding case. 3. The hallux is raised above the level of the other toes, and its basal phalanx is much shorter than that of the third toe. With a single exception, the second metacarpal always has a backward process*. A tubercle is very commonly present upon the posterior edge of the base of the phalanx of the third digit; and the ilio-pectineal processes are generally very well developed. The vomer, wherever I have been able to observe it, has been weak and flattened from above downwards. Three groups are readily distinguishable by osteological characters among the Alectoropodes. The Numidideef differ from the other members of this division in the absence of any backward process of the second metacarpal, and in the obtuseness and somewhat outward inclination of the costal processes. The acromial process of the scapula is also singularly recurved. In all the rest the backward process of the second metacarpal is distinctly developed, and the costal processes are more acute (generally very much so) and pass more directly forwards. Among these the Meleagridce are peculiar in three respects. 1. The length of the ilium from the centre of the acetabulum to its posterior margin (which may be called the postacetabular length) is greater than the distance from the same point to the anterior margin of the ilium (or preeacetabular length). 2. Viewing the pelvis from above, the postacetabular area is longer than it is broad (fig. 5, p. 300). 3. The furcula is singularly weak and straight (viewed laterally), and has a straight rod-like hypocleidium. In all the other genera which I have examined, the preeacetabular length is greater than, or, in the solitary case of Tetrao cupido, equal to, the postacetabular. The postacetabular area is broader than it is long; the lateral contour of the furcula more curved ; and the hypocleidium expanded antero-posteriorly. The great series of Galline, Pavonine, Phasianine, and Tetraonine birds included under the title of Phasianidce, which offer these characters, present two types of structure, the one of which may be termed Galline, and the other Tetraonine, and which are well defined and contrasted in their extreme forms, though I am by no means clear that they do not graduate into one another. * M. Blanchard (/. c. p. 99) gives the presence of this process as a universal character of the "Gallinaces," merely mentioning that "dans les IIoccos et les Penelopes elle s'affaiblit beaucoup." t That is to say, the species of the genus Numida. I have seen no skeletons of Agelastus or Phasidus. |