ijo 



ANNALS OF SCOTTISH NATURAL HISTORY 



Number of Daphnia at first 



a to ?'=the young of first 

 10, or lox 20 x 9 

 And a 1 = 2OO x 20 x 7 . 



, , b l = 200 x 20 x 6 . 



, , c 1 = 200 x 20 x 5 . 



, , d l = 200 x 20 x 4 . 



,, ^ 1 = 2OOX 2OX 3 . 

 ,, / 1 = 2OO X 2O X 2 . 

 , , 1 = 2OO X 2O X I . 



The above is a slightly extended and modified copy of a table prepared by my 

 son, Mr. Andrew Scott. 



Though in the preceding remarks Daphnia pulex only 

 has been considered, there are many others of the entomostraca 

 equally prolific. But though the fecundity of micro-crustacea 

 were considerably less than that shown, it would still be 

 sufficient to fill up in a short time even an extensive blank 

 that some destructive but temporary cause may have produced. 



" Full nature swarms with life ; one wondrous mass." 



COWPER. 



The natural habitat of the freshwater entomostraca is the 

 still water of lakes, ponds, ditches, and those parts of streams 

 or rivers where the current is slow and cumbered with water- 

 plants : entomostraca may be found in all such places. 

 Running water is not their natural resort, and when they 

 happen to be in such a situation they are usually there 

 against their will. Nevertheless an exodus of Copepoda such 

 as that observed by Mr. Tullis is not unknown to those who 



