364 MR. W. p. PYCRAFT CONTRIBUTIONS l^W- ^7 



stand ovit in sharp conti^ast with the ventral median keel of the 

 body. The horns rise directly upwards for a considerable distance, 

 and being continued backwards along each side of the dorsal 

 aspect, this region is converted into a deep triangle. 



It is to be noted that in the matter of the vomer and its 

 relation to the maxillo- palatines, the skull of Euryceros very 

 nearly approaches the Gymnorhinfe. This is a fact which greatly 

 assists in the difficult task of deciding the true position of this bird 

 in the system. It is further notewoi'thy that the peculiarly 

 inflated condition of the maxillo-palatines in the pre-masillary 

 region may well have been derived from conditions such as obtain 

 in the Gymnorhinte. 



The pterygoid throughout this series is elongated, and round or 

 triangular in section. Basipterygoid processes being absent, this 

 rod extends directly from the quadi'ate to the palatine, and 

 parasphenoidal rostrum. Consequently the principal featiu-e of 

 interest for description here concerns the nature of the palato- 

 pterygoid articulation. Before entering on this subject, however, 

 it maybe remarked that the triangular flange which, in the higher 

 Passeres, e. g. Corvidpe, extends from the rim of the dorsal 

 segment of the cotylus for the quadrate, backwards along the 

 shaft, is in the forms herein described represented by a slender 

 style, forming a V-shaped angle with the shaft of the quadrate, 

 e. g. Sayornis. In many cases, however, it is reduced to a mei-e 

 tubercle, or it may even be absent. 



As touching the nature of the ptery go-palatine articulation. 

 This takes two forms. Generally, the pterygoid terminates 

 distally in a leaf-shaped plate, the inner surface of which is 

 applied to the parasphenoidal rostrum, while the inferior edge 

 thereof glides over the edge of the obliquely ti'uncated proximal 

 end of the palatine. This method of articulation has been derived, 

 as I have elsewhere pointed out (6), fi'om an earlier condition 

 of things wherein the pterygoid extended forward to support the 

 vomer. By segmentation of the pterygoid, and the fvision of the 

 vomerine portion with the palatine, the characteristic palato- 

 pterygoid joint has been formed. In a number of cases, howevei-, 

 a pseudo-primitive condition obtains : the pterygoid, instead of 

 segmenting, preserves its integrity, and fuses with the palatine, 

 e. g. Dicruridpe, Prionopida?, Laniinfe, Gymnoi'hinfe, Malaconotida?, 

 Artamidae, and Yangidae. This fusion of the pterygoid and 

 palatine I have already shown (5) obtains also in the Eurylsemidfe 

 and the Tracheophone Passeres. 



The palatine, distad, has the form of a straight rod which is 

 continued backwards considerably beyond the level of the 

 antorbital plate, terminating in a more or less sharp point. 

 Immediately below the inferior border of the antorbital plate it 

 sends inwards, almost at right angles, a broad bar which gives rise 

 to a long trough-shaped scroll running parallel with the long axis 

 of the skull, and with its concavity turned towards the middle line. 

 The upper edge of the scroll affords support to the vomer and 

 pterygoid, while the inferior margin is free, and with its fellow of 



