14 Mr. W. P. Pycraft on the 



Whilst in Erithacus and Turdus the tensor patagii brevis 

 sends off a very delicate slip to the patagial fold, and 

 ultimately, by a few extremely delicate fibres, to the tensor 

 patagii longus, Zeledonia, Saxicola, and Cossypha only present 

 the merest vestiges of this slip. 



The latissimus dorsi posterior is wanting in Zeledonia, but 

 occurs as a strap-shaped muscle in Saxicola, Cossypha, and 

 Turdus. Since this muscle in undoubtedly Timeliine forms 

 appears as a triangular sheet, filling up the V-shaped space 

 between its anterior border and the hinder border of the 

 latissimus dorsi anterior, it would appear that the strap- 

 shaped form which it presents in Saxicola is a degenerate 

 condition preceding extinction. 



The latissimus dorsi anterior is in all the forms just 

 described a narrow strap-shaped muscle, broadest in Saxicola. 



Of the thigh- muscles the only one which offers any features 

 of interest is the femoro-caudal, which, in Zeledonia, is very 

 slender and is inserted by a relatively broad and long sheet 

 of tendon. In Erithacus, Cossypha, Merula, and Cisticola 

 the muscle continues fleshy almost to the point of insertion. 

 Saxicola, as well as Crateropus among the Tiraeliidse, agree 

 with Zeledonia in presenting a long tendinous insertion. 



Muscles of the Syrinx. 

 Since it has been suggested that Zeledonia might prove to 

 be an ally oiXenkus, one of the Anisomyodean Passeres, it is 

 necessary to refer to these muscles and to remark that they 

 are typically Oscinine. 



IV. Osteology. 



Careful study of the skull, sternum, and shoulder-girdle of 

 Zeledonia leaves little doubt but that this bird must be 

 regarded as one of the Turdidae. The skull, however, 

 presents one or two relatively important features, which may, 

 perhaps, be regarded as primitive characters. 



The Skull (PI. II. figs. 7, 9).— The Thrush-like characters 

 of the skull are to be found in the form of the tympanic 

 cavity and of the palate. These points of common resem- 

 blance, it must be remarked, by no means leap to the 



