172 Journal of Comparative Neurology. 



complete semi-circle. The cephalic, ventrally concave curva- 

 ture is strongest at the Sylvian region ; the caudal, ventrally con- 

 vex curvature is strongest in the pons region and is much shorter 

 cephalo-caudad than the other curvature. As a result of these 

 flexures the olfactory bulbs are directed ventrad, or even a little 

 caudad, instead of cephalad and the spinal cord seems to be 

 directed at first almost dorsad. The prosencephalic flexure, 

 then, is longer than the pons flexure and so extreme as to bring 

 the olfactory bulbs into close proximity to the chiasm. The 

 chiasm itself is crowded caudad so as to appear in ventral view 

 almost as if superposed upon the pons. This flexure of the 

 brain is but an extreme application of the general compactness 

 of the avian brain and is due to the unusual curvature of the 

 whole head, which in turn is correlated with the feeding habits 

 of this bird. 



Although the prosencephalic flexure occurs mainly in the 

 Sylvian region, yet the Sylvian fissure proper is not so deep as 

 in many other birds. The dorsal fissure also is shallow and wide 

 and disappears entirely caudad. It originates in the median line 

 about one-third of the length of the prosencephalon behind the 

 front of the latter, passes obliquely caudo-laterad and fuses with 

 the wide Sylvian fissure. In this latter respect it differs from 

 any of the brains figured by Professor Turner in his monograph.^ 



The crebrum is not only shorter, but narrower and shal- 

 lower than that of the snipe, Gallinago wilsoni. The relative 

 mass of the prosencephalon, estimated by Turner's method (i. e. , 

 the cube root of the product of length, breadth and depth 

 — see Vol. I, pp. 58—61) gives 69.9 as compared with 75.2 for 

 the snipe. The front part of the cerebrum is narrow and unu- 

 sually shallow. All things considered, this is one of the most 

 difficult of the American birds to which to apply any system of 

 linear measurements. Any conclusions of taxonomic value 

 which might be drawn from the measurements of this brain, as 

 given in the appended table, must be interpreted with caution, 

 in view of the extreme flexion and of the other peculiarities 

 presented. 



'C. H. Turner, " Morphology of the Avian Brain," this Journal, Vol. I. 



