572 



THE AMERICAN NATURALIST [Vol. LI 



work the concentration of the agent and the length of treatment 

 should be studied in greater detail. 



Robert T. Hance 



Botanical and Zoological Laboratobies, 

 University of Pexxsylvania, 



CONCERNING A MORPHOLOGICAL PREDICTION FROM 

 DISTRIBUTIONAL DATA AND ITS SUBSEQUENT 

 VERIFICATION^ 

 All species of the genus Salpa are notable for their two alter- 

 nating generations. One, known as the "solitary" generation, 

 pn)duecs offspring by budding and the buds, when fully mature, 

 constitute what is known as the ''aggregate" generation, or, as I 

 shall call tlicm, zooids. Each zooid produces, sexually, one of the 

 solitary generation, the embryo being nourished and carried 

 within the ))ody of the zooid until after it has begun to form 



The relation between the two generations, however, is not 

 simple ; and as there seems to be a widespread misconception re- 

 gardiny- this relation, it is well to correct it. 



On.' ^rrv ilir si;i!ciiiciit iu Ttriich of the literature that the sol- 

 ir.n;. , - \u;il. that the aggregate generation is 



sr\i;. . and that the developing embryo of the 



The solitary tonti. or female, produces immature males by 

 l)n(l(lini!. within the body of each of which the mother tucks 



li.-i..". UH-niv'f.-rtiliJt inn thr (>L is suspended by means of a 

 i".-i'iili/.!n- .hirt, whirh ..[... IIS iiitn ihr rluara. into one of the blood 



