Contents of Volume XLV 



No. i. JULY, 1923 



Twenty-fifth Annual Report of the Marine Biological Labora- 

 tory .' i 



ESSENBERG, J. M. Sex-Differentiation in the Viviparous 



Teleost Xiphophorus helleri Heckel 46 



No. 2. AUGUST, 1923 



CROZIER, W. J., AND SNYDER, L. H. Selective Coupling of 



Gammarids 97 



MAST, S. O., AND IBARA, YASUSHI. The Effect of Tem- 

 perature, Food, and the Age of the Culture on the Encyst- 

 ment of Didininm nasutum 105 



VISSCHER, J. PAUL. Feeding Reactions in the Ciliate, Dilep- 

 tus gigas, with Special Reference to the Function of Tri- 

 chocysts 113 



No. 3. SEPTEMBER, 1923 



PEARSE, A. S. The Growth of the Painted Turtle 145 



BODINE, JOSEPH H. A Note on the Toxicity of Acids for 



Mosquito Larvce : . . 149 



GALTSOFF, PAUL S. The Amceboid Movement of Dissoci- 

 ated Sponge Cells 153 



HEGNER, ROBERT W. Observations and Experiments on 

 Eiiglenoidina in the Digestive Tract of Frog and Toad 

 Tadpoles 162 



No. 4. OCTOBER, 1923 



CHILD, C. M. The Axial Gradients in Hydrozoa. V, 



Experimental Axial Transformations in Hydroids 181 



HARGITT, CHARLES W. The Digestive System of the Periodi- 

 cal Cicada. II, Physiology of the Adult Insect 200 



HICKERNELL, L. M. The Digestive System of the Periodical 

 Cicada, Tibicen septendecim Linn. Ill, Morphology 

 of the System in the Nymph 213 







111 



