The Relations between Marine Animai and Vegetable Life. 



389 



Part 2. The Fouling Eifects of Animai Life ou the Water. 



The Effects of Animals in General. 



Thus far the purification of the water by various forms of vege- 

 table life has been the subject of discussion. We now enter upon 

 the other side of the question, the fouling of the water, especially 

 with reference to animai life. Thus the contamination from vegetable 

 sources seems, in the case of sea-water at least, to be in comparison 

 only slight and uuimportant, and those cases in which it does enter 

 in bave already been referred to in the first portion of this paper. 



In order to estimate the fouling effect of an animai, several 

 individuals were placed for a known tìme in a known volume 

 of water, and were then removed and weighed. In a portion of 

 the contaminated water larvi« were grown, whilst another portion 

 was subjected to chemical analysis. In the subjoined table the 

 results obtained are given. Here it will be seen that, in addition 

 to the absolute Variation produced in the size of the larvai, the values 

 for the effect produced by 100 granis of the animai kept for one 

 hour in one litre of water bave also been calculated. By this means 

 the results obtained with diflferent animals under dififerent conditions 

 are directly comparable. Similarly also the amounts of free and 

 organic ammonia added to the water by keeping 100 grams of the 

 animai in one litre for one hour are given as well as the absolute 

 composition of the water. 



'A 



Animals used 



.3 — 



3 o 



r^ a> 



o/o Va- 

 riati un 



per 

 100 gm. 

 p. litre 

 p.hoiir 



Composition 



of fouled 



water 



Var., per 1 00 gm. 



per litre per hour 



in amoiint of 



free lorgan. free organic 

 NH;ì I NH3 NH3 NH3 



45 

 53 



51 

 66 



112 

 49 

 50 



71 



44 



111 

 72 



1 Fish [Scorpae/ui udulata] .... 



2 Fish [Balistes capriscus and Julis 

 vulgaris 



4 Crabs [Pachi/grapsus marmoratus) 



30 Molluscs [Cerithium vulc/atmn, 



Fasciolaria liquaria, Trochus tur- 



hinatus) 



48 Molluscs [Cerithium vulgatuiìi) . 



3 Holothurians [Holothuria tuhiilosa) 

 3 Holothurians (same) + Ocm. Ulva 



per 1 



3 Holothurians (same species) . . 

 1 Grab + 3 Anemones [Pagurus & 



Adamsia) 



3 Anemones [Adamsia rondeletii) . 



1 Medusa [Rhizostoma pulmo) . . . 



Mittheilangen a. d. Zoolog. Station zu 



+ 1.4+ 1.8 



+8.3 

 + 1.6 



+2.8 

 +4.8 

 +5.0 



.4 



+4.7 



-1.5 

 — .6 

 —2 *> 



.377 



.090 +.228- .028 



+ 12.8 .739 1.190J+.725 

 + 2.1 .854 .676 +.801 



+ 1.3 



+ 1.1 



+ 2.0 



- .1 

 + .9 



- 1.0 



- .5 



- 1.9 



+.134 

 +.004 

 +.063 



+.039 



+.538 

 +.112 

 +.125 



+ 1.577 

 + .698 



+ .094 

 + ,.016 

 + .031 



+ .022 



+ .084 

 + .093 

 + .126 



Neapel. Bd. 13. 



26 



