374 MR. W. p. PYCRAFX — CONTRIBUTIONS [Apr. 9, 



insertion, where it becomes suddenly tendinous. In the Hirun- 

 dinidfe it is also of great size, and joins the delfoideus major 

 longus to form a short, thick, fleshy column to be inserted into 

 the ectepicondylar process. The d. m. longus is a relatively 

 slender muscle in both these families ; and this is true also of 

 the Gymnorhidpe and Paradiseida?. 



The Families brought together in this paper, are, it is con- 

 tended, all more or less closely allied. And this relationship is 

 nowhere more easily traced than in the skull. 



Throughout this series, the maxillo-palatine processes retain 

 more primitive characters than in any of the remaining Diaci'o- 

 myodean Passeres : and these would seem to have been derived from 

 the Pittid?e and Tyi'annidfe. In the Tyrannine palate, as has 

 already been i-emarked, the maxillo-palatines take the form of a 

 pair of broad triangular plates ; the apex of the triangle tending 

 to curve towards the base of the skull. 



The Diacromyodean types show an ever increasing tendency to 

 transform this triangular plate into a long slender rod, curving 

 towards the base of the skull, and terminating in a more or less 

 spatulate, and sometimes inflated free end. 



The Campophagida? and Muscicapidas well illustrate these 

 phases, the more primitive showing the triangular, the moie 

 specialised the rod-like form, Other Families herein described 

 show further and more peculiar charactei'S of the palate which 

 will be more particularly referred to in due coiu'se. 



Broadly speaking, the Families now under consideration may be 

 divided into two Groups — Flycatchers and Shrikes. 



The Flycatchers (Muscicapidse and Campophagidfe) most nearly 

 approach the Tyrannine tvpe ; and are therefore to be regarded 

 as the more primitive. Herein the maxillo-palatines are more oi- 

 less triangular, and there is an ossified septum nasi dividing the 

 palatine foramen into right and left moieties. Commonly, the 

 inferior boi-der of this nasal septem is expanded to form a 

 flange. 



The Hirundinidfe are generally regarded as very nearly allied 

 to the Muscicapidse. That they are related to this Family is, 

 I think, a fact ; but this alliance does not appear to be so 

 close as is generally supposed. The Swallows indeed are a race 

 apart. 



In other words, the Swallows and Flycatchers are to be 

 regarded as derivatives of the same generalised stock which have 

 developed along independent, and more or less parallel lines. 

 In so far as the skull is concerned, the Swallows recall some of the, 

 presumably, more primitive Tyrannid^e. And this is especially 

 the case with regard to the specialised condition of the maxillo- 

 palatines and the relation of the palatines to the prsemaxilhi : 

 characters which appear to be, to some extent, adaptive, and 

 coiTelated with the shortening of the beak and widening of the 

 gape which apparently becomes necessary to ensure the successful 



