THE EMBRYOLOGY OF STOMOTOCA APICATAi 
SAMUEL RITTENHOUSE 
Professor of Biology, Olivet College, Michigan. 
THIRTY-TWO FIGURES 
INTRODUCTION 
The material for this research was secured, and the observa- 
tions on the living forms were made, during the summers of 1903 
and 1904 while I was occupying a table at the United States 
Bureau of Fisheries' Laboratory at Beaufort, North Carolina. 
Stomotoca is not very abundant in the harbor at Beaufort. I 
found it as early as the middle of June. It is most plentiful dur- 
ing July and early in August. A few specimens may also be taken 
until early in September. The eggs were obtained from medusae 
captured between July 10 and August 5. The adult animals 
could not be secured in large numbers; and, owing to the fact that 
each female lays only a few eggs, the material for embryological 
study was limited. Therefore the greater part of the work, the 
results of which are embodied in this paper, was done with living 
material. All the drawings with the exception of those of sec- 
tions were made from camera sketches of the living forms. Blas- 
tulae and planulae ranging in age from five to twenty-seven hours 
were preserved and sectioned for the study of the various stages 
in the formation of the entoderm and the other features of develop- 
ment which make their appearance during this period. 
^ 1 wish to acknowledge my obligations to the Honorable George M. Bowers, 
Commissioner of Fisheries for the privileges afforded me at the Fisheries' Labora- 
tory; and also to thank Dr. Caswell Grave, Director of the Laboratory, for help 
and suggestions. The work was finished at the Biological Laboratory of the 
Johns Hopkins University. Much interest was shown and kind suggestions were 
offered during my work by the late Professor W. K. Brooks. 
