372 MR. W. P. PYCRAFT CONTRIBUTIONS [Api*. 9, 



tubercle, while on the opposite side of the tibial shaft, and some 

 considerable distance above the entocondyle, is a similar condyle, 

 generally much larger. These serve as points of attachment for 

 the ligamentum transversum, which keeps in place the tendon 

 of the tibialis anticus. The ento- and ectocnemial crests differ 

 considerably in their relative development. Thus in the Tyran- 

 nidfe they are but feebly developed ; in the Pittidse the ento- 

 cnemial is large, the ectocnemial very small ; while in the 

 Gymnorhinfe, for example, both are very strongly developed. 

 The size of these crests does not appear to vary in proportion as 

 the wings are less used. But a more careful study of the habits 

 of the different types which present these differences may show 

 that they vary as the legs are used in perching — as in birds 

 haunting thick undergrowth and flying but little — or walking. 



The tar so -metatarsus is short in arboreal types, such as the 

 Tyrannidip, long in those which spend their lives for the most 

 part on the ground, as in the Pittidfe and Gymnorhinee. In all, 

 the ovitev border of the shaft is produced backwards into a bladder- 

 like ridge ; and in some this is very marked, as in Gymnorhina 

 and Paradisea for instance. The hypotarsus is complex, and 

 takes the form of a backwardly pi-ojecting spur pierced by several 

 foramina. 



The trochlese are, as it were, cut out of the flattened and 

 expanded distal end of the shaft, so that all lie in the same plane. 

 The ento- and mesotrochlea are subequal in length, but the ecto- 

 trochlea is slightly shorter, and genei^ally also mvich smaller : pre- 

 senting only a narrow rim for the articulation of the digit. 

 Only the mesotrochlea indeed presents the typical grooved 

 articular surface. 



The anterior face of the proximal end presents charactei-s which 

 may prove of service. Thus in the Tyi'annida?, for instance, this 

 region is rounded on its outer bordei-, and bears a tubercle for the 

 insertion of the tibialis anticus ; while below the inner cotylus is 

 a bony bridge — the ossified ligament which guides the tendon of 

 the extensor longus digitorum. In the Gymnorhinse this region 

 of the shaft is deeply hollowed : the extensor bridge is ligamentous, 

 and the shaft is perforated by two small foramina, one on either 

 side of the median digit. The Pittidfe appear to agree with the 

 Tyrannidse in these particulars, which appear to obtain also 

 throughout the rest of the Families herein described. 



ix. Summary. 



I have ventured, on the evidence chiefly of osteological and 

 myological characters, to associate many Families which have 

 hitherto been separated, often widely. Furthermore I have en- 

 deavoured, in the course of this summary, to show that the ranks 

 of these Families must be enlai-ged to receive forms which till now 

 have been regarded as having no affinities therewith. 



It Avill be remarked that I have included in this paper the 



