Osteology of the Chatham Island Snipe. 707 



rather than actual, being covered with a transparent film. 

 They are also indicated in Homoptilura. Other points to be 

 noticed from a lateral view of the skulls under consideration 

 are as follows : — 



(1) The relative length of the quadrato-jugal bar, as 

 compared with the outer process of the nasal of either side, 

 and their relative shapes. 



In the Rusticoliiie type these processes are as nearly as 

 possible equal, and if an imaginary line be drawn, so as to 

 join their proximal extremities, an equilateral triangle is 

 produced. In the Rusticoline type both these processes are, 

 moreover, flattened or ribbon-shaped, and their angle of 

 junction is acute. In respect of both these characters the 

 Chatham Island Snipe is Rusticoline, although these points 

 in text-figure 12, B are not quite clearly shown. Homoptilura 

 is also Rusticoline in this respect. 



In the typical Gallinagiue form the quadrato-jugal bar is 

 distinctly longer than the outer nasal process, and makes 

 a right angle with it. Both processes are thin and rounded, 

 instead of flattened. In the Jack-Snipe much the same 

 condition as regards relative length of these bones and the 

 angle formed at their junction is to be noticed, but in 

 this form there is a considerable amount of abnormality 

 in the form and shape of the maxilla and jugal. In the 

 Painted Snipe the condition observed is Tringine, in the 

 Dunlin Eroliine (for differences, compare ' Ibis,' 1915, 

 p. 615). 



(2) In the Chatham Island Snipe and in the Jack-Snipe 

 the internasal septum is markedly deficient, as compared 

 with the conditions noticed in the Woodcock and Common 

 Snipe (and its allies^ so far as ray investigations have 

 extended) . 



In both these latter forms the groove for the nasal branch 

 of the 5th nerve is a prominent feature (c/. text-figures 12, 

 C and D). In the Chatham Island Snipe and the Jack- 

 Snipe the lower end of the nasal groove is notched or 

 deficient. 



SER. X. VOL. III. 3 B 



