356 MR. W. p. PYCRAPT — CONTRIBUTIONS [Apr. 9, 



with in this paper, the temporal fossa terminates immediately 

 above the tympanic cavity : excepting the Muscicapidse, where it 

 is either extremely reduced or absent. 



The postorbital process is obsolete in Phytotoma — another of 

 several features which this Family shares with the Pittidee, In 

 the Tyi'annidse it is only very feebly developed ; and the same is 

 true of the Hirundinidse, Muscicapidse, Campophagidte, and the 

 LaniincB at least among the Laniidfe. 



The reduction of this process is due to specialisation : and in 

 the forms here dealt with, it has been accompanied by an equally 

 gradual reduction of the "temporal fossa." In all these cases, 

 the process has travelled downwards, nearer and nearer to the 

 jjrocessios zygomaticus squamosi, and this is nowhere better shown 

 than in a comparison of the skulls of Muscicapa and Terpsiphone 

 for example ; since in the latter the two processes are almost 

 confluent, and further, by the obliteration of the " temporal 

 fossa " the supei-ior margin of the tympanic cavity has extended 

 forwards to join the postorbital process. In the Muscicapidfe this 

 margin has crept forwards no farther than the hinder border of 

 the remnant of the fossa. In the Laniince, the reduction of the 

 postorbital process has been accompanied by a corresponding 

 increase in the size of the processits zygomaticus squamosi, which 

 has, in consonance with the use of the jaws for tearing prey, 

 shifted forwards so as to lie midway between the squamosal 

 articular surface of the quadrate and the postorbital process. 



Among the Laniiform-types, the Gymnorhidse and Malaconotidpe 

 have the postorbital processes of large size, and so also have the 

 Dicruridse, Eurycerotidse, Artamidfe, Yangidse, and Prionopidse. 

 The Gymnorhidee, Artamidse, and Vangidse, by the way, are 

 peculiar in that the zygomatic process of the squamosal is 

 bifurcate : or, in other words, mesiad, and a little in advance, of 

 the normal process, there is found a second though slighter peg. 

 So far I have not met with this in any other families. 



The orbits present no very important characters in this 

 connection. Only in the Gymnorhidfe and Vangid?e, it would 

 seem, is the orbito-sphenoid ossified, or the interorbital septum 

 perforated by but a single small fenestra. All the remaining 

 genera herein dealt with have the orbito-sphenoid but slightly, if 

 a,t all ossified, and the interorbital septum pierced, either by a 

 long narrow upper slit and a wider, inferior fenestra, or by one 

 large fenestra absorbing almost the whole septum as in Paradisea. 



The Ethmoidal Region. — With that portion of the mesethmoid 

 which takes part in the formation of the interorbital septum I 

 have just dealt. The lateral mesethmoidal wings of the antorbital 

 plates — called by some pre-frontals — which bound the orbit 

 anteriorly, present but few features of special note. Gymnorhina 

 is somewhat remarkable in this respect inasmuch as these plates 

 extend outwards and upwards, one on either side, to form a pair of 

 wings of considerable size, and projecting laterally on either side 

 of the nasals, thus greatly increasing the depth of the orbital 

 chamber. 



