OCR Text |
Show 1890.] THE STRUCTURE OF PSOPHIA. 333 Psophia shows the following points of difference from Grus:- (1) The inner margin of the palatines is not greatly bent downwards to form the inner lamina. (2) The vomer ends on a level with the anterior margin of the maxillo-palatines, it is anteriorly thin and compressed. (3) There is no conspicuous foramen formed at the junction of the quadrato-jugal with the maxilla. (4) There are no occipital foramina above the foramen magnum. (5) The supraorbital margin is produced into a thin, strong, sharp-edged area. (6) It is holorhinal. (7) The interorbital plate is much less vacuolate. (8) The palatines are wider behind than in front. (9) The temporal fossae are not so extensive. (10) The surface of the maxillary process of the nasal bone is directed outwards. Psophia shows the following points of difference from Ocydromus :- (1) The inner margin of the palatines is not greatly bent downwards. (5) The supraorbital margin is produced into a sharp edge. (7) The interorbital plate is not largely vacuolate. (8) The contrast between the wider posterior and narrower anterior part of the palatines is not so marked. (9) The temporal fossae are not nearly so well marked. (11) The lateral ethmoid processes come more nearly into contact with the descending process of the lachrymal, which very nearly reaches the jugal. (12) The skull is relatively broad in the interorbital region. (13) The articulation of the quadrate is not hidden by a downward growth of the squamosal. In all these points Psophia also differs from Fulica and Aramides, Crex and Porphyrio ; but, in the latter, characters Nos. 9 and 13 offer less-marked differences. The vomer in Crex and Porphyrio is a much broader bone, though ending in a point. Psophia shows the following differences from CEdicnemus l :- (2) The vomer does not extend beyond the anterior end of maxillo-palatines. (3) There is no conspicuous foramen at the junction of the jugal with the maxilla. (7) The interorbital plate is not so vacuolate, though the vacuo-lation is slight in CEdicnemus. (9) The temporal fossae are not so well marked. 1 The sharp edge of the supraorbital region is largely due in Psophia to a chain of supraorbital bones, which were first made known by Parker (" O n the Osteology of the Kagu," loc. cit. p. 50o). It is possible that CEdicnemus and Ehinochetus, which agree in this particular with Psophia, will be found to have a similar series of ossicles which in the adult become completely fused with the frontals and parietals. PROC. ZOOL. Soc-1890, No. XXIII. 23 |