Sil CARL CASKEY SPEIDEL 
found in any of the fishes. The Dahlgren cells of most of the 
fishes examined resemble very much the early developmental 
stages of the Dahlgren cells in skate embryos and young skates. 
LITERATURE CITED 
1 Dautcren, U. 1914 On the electric motor nerve centers in the skates 
(Rajidae) Science, vol. 40, no. 1041, pp. 862-863. 
2 Spripen, C.C. 1919 Gland-cells of internal secretion in the spinal cord of 
the skates. Pub. 281, Carnegie Inst. of Wash. 
