152 MR. W. r. rVCKAFT ox TJIE OSTEOLOGY [Feb, 20. 



enable me to say iiiucb concerning the form of tlie I'elvis in the.se 

 somewhat heterogeneous groups, but those geneiu which I have ,so 

 far examined in tliis connection show considerable specialisation in 

 adaption to climbing habits. In the smaller Synallaxine species 

 the pelvis resembles that of the Philepittida?, having the i.schia 

 widely expanded posteriorly and prod viced into a. long rod-like 

 foot bent sharply on its long axis, but the pre-acetabular ilium is 

 relatively shorter. In tSiptornis the pre-acetabular ilia ai'c 

 widely separated, being divided by a deep trough on either side 

 of the synsacral crest ; but in Synallaxis and Ilomorus, by the 

 shortening of tlie transverse process of the supporting vertebra?, 

 the innominate bones almost touch one another above the synsacral 

 crest. In Pseudocolaptes the pi-e-acetabular ilia ai-e subconical in 

 shape and rise to the level of the synsacral crest, but are separated 

 therefrom by a narrow space. The foi'm of the ischium agrees 

 very closely with that which obtains among the more specialised 

 Dendi'ocolaptines : since it turns downwards instead of running 

 backwards beyond the level of the post-acetabulai- ilium : by this 

 means the depth of the hinder region of the pelvis is greatly 

 increased. In Xiphorhynchas and Deadrocolaptes this deepening 

 is especially noticeable ; furthermore, this is associated with a 

 tendency to close up the obturator fissui-e by the ossification of 

 the tendinous fascia stretched between the inferior' border of the 

 ischium a,nd the pubis. In Xipliorhynchus this newly ossified 

 matter hangs down from the ischium in the form of a delicate 

 curtain of bone and is continued forwards and downwards to form 

 a, bi-oad bony plate enclosing the obturatoi' foramen. 



The pehis of Batara, one of the Formicariida', presents some 

 extremely interesting features. In many respects resen)V)ling the 

 pelvis of Dendrocolajytes, it diflers therefrom in having the dorsal 

 1)oi-der of the ja-e-acetabular ilium strongly arched, and this curve 

 is followed by the synsaci-al ciest which lies between. The ischium, 

 in its general shape and chai-acters, also closely resembles that of 

 J)endrocolaj)tes. but it ditfers therefi'om mainly in that it fuses 

 completely with the pu))is. which is unusually broad and also very 

 short. 



In all these pelves the fovea lumhalis is extremely small, and the 

 fovea ischiadica and pudendalis are confluent. 



vii. TiiK Pkctoual Limb. 



Thepectoi'al limb in the groups here described presents a some- 

 what remarkable uniformity even in structural details : so much 

 so that it would be difficult, on the e^ddence of the wing alone, to 

 determine to which of these families the skeleton belonged. 



With but few exceptions the forearm is the longest segment of 

 the wing, but then is ne\"er markedly longer; the arm and manus 

 sire subequal. There is no coraco-humeral groove, and the 

 characteristic pit foi' the hraehialis anticas is situated below and 

 pi'oxiniad of ilic \dnar coinlvlc. 



