AN INTRODUCTION TO A.\ / \\MOLOGY. 



tended by the current. Much of the coating of dirt with which 

 thoc rw mmcr is due to ii caught in tb 



. I ha\ oi .he nets taking their 



in them; but 1 cannot doubt that th< .uie to trap 



or other anima .ire being carried down 



for the larvae of the sub-family to which these net-builders bci- 

 the known to be carnivorous. It should 



noted here, however, that tl: r number ot caddice-wonn> are 



herbivorous. 



There are many caddice-worms that build their cases of stones; 

 some of these cases are very regular in form. One of the common 

 kinds resembles a slightly tapering cornucopia, nuuk I] -rains 



of sand, cemented together with -real regularity. Another i 

 of a shorter tube, to each side of which are fastened one or t\\o 

 larger stones, as if to keep it in position (Fig. 197). But moi\ 



i 



FIGS. 197, 198. Cases of Caddice-worms. 



markable than either of these is the case (Fig. 198) which sc closely 

 i form the shell of a snail that it has been described as 

 such by several conchologi>ts. 



We find among the caddice-worms carpenters as well as m,i 

 And tilt s among the builders of wood as great a vann 



architectural tastes as among the builders of stone. I Yobably the 

 nio-t familiar of the form><>: i.ide of wood is that represented 



in Fig. 199. This i> made of irregular pieces of wood arranged in a 



199, 200.- Cases of Caddice-worms. 



longitudinal manner. Much more likely to attract attention is the 

 case composed of sticks placed at right angle's to the body (Fig. 200). 



