CHORD ATA 



433 



Bhahdopleura normani has been dredged in the Hardanger 

 Fjord, off the Shetlands, and off one of the islands of the 

 Tristan d'Acunha group. It consists of an irregularly branch- 

 ing colony attached to foreign bodies. The zooids are very 

 minute; they are connected by a stem, and the whole is 

 ensheathed in a tubular investment, probably secreted by the 

 proboscis (epistome). A pair of processes bearing tentacles, 

 into which the cavity of the collar space is continued, exist. 



-+— 6 



Fig. 250. — Side view of Rhahdopleura normani. Partly diagrammatic. 

 Lanlcester and Fowler. 



After 



1. Proboscis (epistome). 



2. Mouth. 



3. Stomach. 



4. Intestine. 



5. Anns. 



6. Stalk. 



7. Eight tentacular arm, only one row 



of tentacles is shown on each arm. 

 The animal is represented as transparent to show the alimentary canal and notochord. 



8. Notochord. 



9. Dotted line indicating the division 



between the regions of the body 

 and of the collar. 

 10. Dotted line indicating the division 

 between the regions of the collar 

 and of the proboscis. 



and closely resemble the similar structures in Oe^halodiscus. 

 The zooids creep up the tube in which they are enclosed by 

 means of the proboscis, and are retracted by means of muscle 



28 



