iv Content? 



PAGE. 



IX. George L. Stueeter. The Peripheral Nervous System in 



the Hnnian Embryo at the End of the First Month 285 



AYith 3 Plates and 1 Text Figure. 



X. Walter A. Baetjer. The Origin of the Mesenteric Sac 



and Thoracic Duet in the Embryo Pig 303 



With 10 Figures. 



XL William E. Kellicott. The Growtli of the Brain and 

 Viscera in the Smootli Dogfisli (Mustelus canis, 

 Mitchill) ^. 319 



With 7 Plates. 



XII. Harris H. Wilder. The Morphology of Cosmobia. 

 Speculations concerning the Significance of certain 



Types of Monsters 355 



Witli 4 Plates and 3? Text Figures. 



XIII. Mabel Bisiior. Heart and Anterior Arteries in Monsters 

 of the Piceplialus Group : A Comparative Study of 



Cosmobia 441 



With r Plates and 5 Text Figures. 



