\V. P. PYCRAFT— AVES : APPENDIX. 



457 



shows a decided adaptation to the bird's mode of life — clinging to reeds ; and this 

 because the proximal portion of the toes, and especially of the hallux, is markedly 

 expanded and closely granulated, so as to afford a hold of smooth-stemmed rushes. 

 There is no approach to this in the foot of Bradypterus. 



III. Myology. 



The condition of the deltoideus major and gastrocnemius muscles ouly need be 

 described for the purposes of this paper. 



Wing-Muscles. 

 The deltoideus major in Bradypterus is in a condition rather more primitive than 

 that of the Whitethroat and Chiffchaff, but is slightly more specialized than in 

 Acrocephalus ; while in all these genera this muscle has preserved more of its primitive 

 character than is usual among the Passeres. 



Text-fig. 16. 



a 99?. 6.* 



d. m,. b. 



1!|FL J.pt.tr 





Wiug-niuscles of Bradypterus, slightly diagrammatic. 



The longus division (text-fig. 16, d.m.l.) is divisible into two layers. The outer rises 

 from the inner aspect of the expanded free end of the furcula ; while the inner and 

 immediately underlying moiety, which is nearly as large as the outer, arises from the 

 acrocoracoid. These two divisions, obviously derived from a two-headed condition of 

 a single muscle, fuse midway down the arm to be inserted in the form of a thick 

 fleshy stump on to the ectepicondylar process of the humerus, but distinct from the 

 delt. maj. brevis. 



vol. xix. — fart iv. No. 60. — March, 1910. 3 f 



