96 ANNELIDA. 



the capillary setce are in the notopodium and the uncini are in 

 the neuropodium. With the peristomium they form a "thorax" 

 of nine somites. In the somites which follow, the "abdo- 

 men," observe that the uncini and the capillary setae stand in 

 the reverse order. 



4. Find the ventral shield-glands. A furrow (sulcus or 

 faecal groove) divides them into pairs toward the posterior end 

 of the worm. 



A drawing is desirable. 



HYDROIDES. 



This is a member of the family Serpulidae. Study living 

 specimens and their heavy calcareous tubes. Notice the banded 

 branchice (modified palps) and the dorsally placed operculum, a 

 modified gill filament. Look for "eyes" on the gill filaments. 



When eggs and sperm are mature these animals will shed 

 them immediately upon being removed from their tubes and 

 placed in sea-water. The larvae are typical trochophores. 



A drawing is desirable. 



Hatschek: Entwicklung der Trochophora von Eupomatus uncinatus, 

 Philippi. (Serpula uncinata.) Arb. Zool. Ins., Wien, 6, 1886. 



Shearer: On the Development and Structure of the Trochophore of Hy- 

 droides uncinatus (Eupomatus). Quart. Jour. Mic. Sci., 56, 1911. 



SPIRORBIS BOREALIS. 



This animal is also a member of the family Serpulidse. 

 Specimens are very abundant along the shore, attached to Fucus. 



1. Study the tube and notice the way in which it "parallels" 

 the form of a small snail-shell. 



2. Remove a live specimen from the Fucus on which it grows 

 and crack the tube away with a needle. Study the animal in 

 a watch-glass with a low power. Identify the gills, the opercu- 

 lum (which serves as a "brood-pouch"), the setce, and the collar. 

 Are there any "eyes" on the gills? 



3. Study the egg-strings which are lodged in the tube, and 

 the young embryos which are to be found in the brood-pouch. 



A drawing is desirable. 



