IV CONTENTS 



No. 4. NOVEMBER 



W. \V. Swingle. Experiments on the metamorphosis of neotenous amphib- 

 ians. Two text figures and two plates (eight figures) 397 



H. P. Kjerschow Agersborg. Some observations on qualitative chemical 

 and physical stimulations in nudibranchiate moUusks with special 

 reference to the role of the 'rhinophores.' Two figures 423 



DwiGHT E. MiNNicH. A quantitative study of tarsal sensitivity to solu- 

 tions of saccharose, in the red admiral butterflj'. Pyrameis atalanta 

 Linn. One figure 445 



Stefan Kopec. Mutual relationship in the development of the brain and 

 eyes of Lepidoptera. One plate (six figures) 459 



Stefan Kopec. Physiological self-difTerentiation of the wing-germs grafted 



on caterpillars of the opposite sex 469 



E. J. Lund. Experimental control of organic polarity by the electric cur- 

 rent. II. The normal electrical polarity of Obelia. A proof of its 

 existence. Two figures 477 



