No. I.] MESENCHYME IN CERTAIN LARVAE. 



23 



3. In both larvae prior to such fixation cells may be found, 

 singly or in pairs, which pulsate in more or less rhythmical 

 contractions until their branches become fastened to the larval 

 tissue, when the pulsations cease. 



4. Both larvae, accordingly, show a well-marked transition 

 from automatic pulsations to muscular contractions dependent 

 upon the central nervous system. 



State Normal School, Westfield, Mass., 

 April 18, 1898. 



