458 



THE 1 MERK W \\1LR\J 1ST 



[Vol. XLI 



be mentioned the tendency to multiplication of ganglionic out- 

 growths observed by Metcalt in fcalpa. 



4. Embryology, — Knowledge of tunicate development has prog- 

 ressed in numerous ways during the decade. According to my 

 judgment two of these are particularly signihcant to the general 

 biologist. They pertain to the verv^ early embryonic life and to 

 the multiplication of branchial stigmata. Among the investiga- 

 tions of the early embryo those by Conklin easily hold hrst place. 

 To the embryologist, one set of facts brought out by Conkhn 

 stands with special prominence in the midst of many that are 

 important. These relate to the cjuestion of organization in the 

 unsegmented egg. Conklin's figures seem to furnish strong sup- 

 port for his statement that " it is doubtful whether any other case 

 of cytoplasmic localization hitherto reported is more remarkable 

 than that which has been described in the preceding pages for the 

 ascidian egg." 



Important as are these particular truths of ascidian develop- 

 ment emphasized by Conklin's observations, there are other as- 

 pects of his work which appeal particularly to the general zoologist. 

 In a resume of what is known about cytoplasmic localization 

 the author savs: — "The annelids do not approach the chor- 



