236 



THE INVERTEBRATA 



e.^" '''' ''lot. thor. 



Fig. 176. Tubicolous Polychaeta. Terebellid {Loimia). A, Side view of 

 young form taken from its tube. A', Side view of pelagic larva in its gelatinous 

 case. After Wilson. Chaetopterus pergamentaceiis. Original, B, Side view of 

 worm in tube. Arrows show the direction of the water currents. B', Dorsal 

 view of anterior part to show the ciliated grooves. Original. Arrows show 

 the direction of the food currents, col. peristomial collar; e. eye; tent. 

 tentacle; up. I. upper lip, the lower lip (/./.) is a prominent structure to the 

 right of the tentacles ; ot. otocyst ; not. notopodia ; not. 4, notopodia with en- 

 larged chaetae in 4th chaetiferous segment ; not. 10, food- collecting notopodia ; 

 cup, organ for forming foodballs; fan., mu.fan. muscles for moving fans; 

 neur. neuropodia forming suckers for attachment of worm to tube; abd. 

 abdomen ; gl.sh. mucous glands ; thor. thorax. 



