AMPHITRITE, CISTENIDES, CLYMENELLA 101 



6. The live worm is of a bright pinkish color, due to its 

 red blood. There is only one internal septum and its forms 

 a so-called diaphragm. Anterior to the diaphragm the 

 nephridia are large and excretory in function. Posterior to 

 the diaphragm the nephridia serve as genital tubes. 



A drawing is desirable. 



CISTENIDES (PECTINARIA) GOULDI 



This very aberrant worm belongs to the family Amphic- 

 tenidae. 



1. Study the beautiful tube of sand and the manner in 

 which the grains are fitted together. It is said that the 

 worms can carry the tubes about. 



2. See how the peristomium and the large golden setae 

 close the shell. The setae are said to belong to the second 

 somite. Notice the ends of the tentacles protruding from the 

 tube. 



3. Find the tentacles, two pairs of gills, and the para- 

 podia. Notice how the latter diminish in size posteriorly and 

 how each typically consists of a ridge-like notopodium with- 

 out setae and a reduced neuropodium with long golden setae. 

 If the specimen is complete you can see a much degenerated 

 portion (the scapha) at the posterior end, which serves to 

 close the small end of the tube. 



A drawing is desirable. 



CLYMENELLA TORQUATA 



This worm belongs to the family Maldanidae. It makes 

 tubes of sand and generally lives in sheltered places on sandy 

 or muddy shores. 



1. Study the structure of the tube. 



2. Observe the diameter and length of the worm, the small 

 number of somites, their great length as compared with 

 somites of Nereis, and the reduced parapodia. How many 

 segments are there? Which are setigerous? Notice the 

 characteristic collar on the fifth somite, and the funnel at 

 the posterior end, with the anus within it. The mouth is 



