i6o Journal of Comparative Neurology. 



The measurement given in each case is the ratio of the 

 actual measurement of the part to the entire length of the brain 

 expressed in, hundredths. The symbol •' ./ L. B. D. indicates the 

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

 prosencephalon, thus giving us the means of comparing the bulk 

 of that important part of the brain in different* birds. In 

 Fu'ica the dimensions expressed abDve are: for the rhin- 

 encephalon, length, 14.2; breadth, 18; the lobes project and 

 are not fused: prosencephalon, length, 73 ; breadth, 90; depth, 

 55; ^V L. B. D. 71.22; mesencephalon, length, 27; breadth, 

 22; epencephalon, length, 50; breadth, 33; depth, 38; meten- 

 cep'ialon, length, 40; breadth, 33; depth, 22; length of 

 brain, 22 m m. In the duck we find, for the rhinencephalon, 

 length, 16; breadth, 13; prosencephalon, length, 74; breadth, 

 87; depth, 54; =^v L. B. D 69 3; mesencephalon, length, 33; 

 breadth, 23; epencephalon. length, 26; breadth, 33; depth, 43; 

 metencephalon, length, 50; breadth, 33; depth, 30 ; length of 

 brain, 33 m..r>. In Gailinago wilsoni, •* v L. B. U. is 75.18, while 

 in Ardea heroMi^, it is 58.43, showing how far our species 

 {Fulica, 71.22) is above the herons. 



EMBRYOLOGICAL NOTES ON THE BRAIN OF THE 



SNAKE. 



C. L. Herrick. 

 With Plates XV-XIX. 



A few isolated memoranda from a larger number gathered 

 daring the present year, are here presented, with especial refer- 

 ence to certain morphological problems. 



General Description. The embryos in question repre- 

 sent three stages from Euhe/iia and one from the black snake, 

 the latter being a little older than the oldest garter-snake 

 em')ryo. The youngest embryo is somewhat less mature than 

 the youngest figured by Rathke.^ 



Rathke's embryo possessed but two pairs of gill clefts while 



IRathke, H. Entwicklungsgeschicte der Natter, 1839. Plate I, 

 Figs. 1-5. 



