io8 ANNALS OF SCOTTISH NATURAL HISTORY 



2 contained sixteen organisms each (equal to 32 specimens). Of 

 these 7 were Cyclops (allc?); i Canthocamptus ; 23 Cypris ; 

 and i insect larva. 



i contained seventeen organisms (equal to 1 7 specimens). Of which 

 i was a Cyclops ( c? ) ; and 1 6 Cypris. 



The total number of organisms in the 384 utricles con- 

 taining matter that could be identified, as shown by the 

 preceding records, was 2021. The total numbers were: 

 Cyclops, 535 (454^, 509, 31 ?); Canthocamptus, 6 1 ; Cypris, 

 1415; 2 Cladocera ; 4 small Annelides ; i Rotifer; i 

 Tardigrada ; and 2 insect larvae. 



Dividing 2021 (the total number of organisms) by 

 384 the (number of utricles containing matter that could be 

 identified), we get an average of about 5^- organisms to each 

 utricle, or more correctly 5^2629 organisms. 



Some weeks after the first lot of five hundred utricles had 

 been worked up, three hundred more from the same ponds 

 were examined. This was done in order to ascertain if some 

 of the results brought out by the examination of the first lot 

 would be repeated, as for example the preponderance of 

 Cypris, and the large proportion of males to females among 

 the Cyclops. In the examination of this second lot, empty 

 utricles were discarded. 



Of the 300 utricles, 1 1 contained organic matter, but too 

 much decomposed to be distinguishable ; the remaining 289 

 contained matter that could be identified. 



50 of the 289 utricles contained one organism each (equal to 50 

 specimens). Of these 23 were Cyclops (206*, 2$, i ?) ; 8 

 Canthocamptus ; 18 Cypris; and i "Water-mite." 



36 contained two organisms each (equal to 72 specimens). Of 

 these 31 were Cyclops (276*, 3?, i?); 2 Canthocamptus; 

 37 Cypris; i "Water-mite"; and i small Annelide. 



29 contained three organisms each (equal to 87 specimens). Of 

 these 24 were Cyclops (22$ , i <j? , T ?)j 3 Canthocamptus ; 58 

 Cypris ; and 2 insect larvae. 



23 contained four organisms each (equal to 92 specimens). Of 

 these 1 4 were Cyclops (no, 2 ? , i ?) ; i Canthocamptus ; 7 7 

 Cypris. 



19 contained five organisms each (equal to 95 specimens). Of these 

 20 were Cyclops (all $ ) ; 3 Canthocamptus ; and 72 Cypris. 



