PLATE XCIX. 



Fig. 



1. Tubes of Polydora ciliata, Johnst., attached to free surface of rock in which is the 



tunnel. The tentacles of the living form extend from that on the right. Enlarged. 



1 a, Contracted tentacle of the same showing its general structure in life. a, ciliated 



groove ; b, continuation of coelom ; c, blood-vessel. Magnified. 



2. Lateral view of the head of Proclymene Millleri. Enlarged. 



2 a. Another example in which the cephalic peak is less developed. Enlarged. 

 2 b. Dorsal view of the cephalic plate. Enlarged. 



2 c. Anal disc of the foregoing. Enlarged. 



3. Caudal region (thickened rim and disc) of Proclymene I. Enlarged. 



4 and 4 a. Views of the anal disc of Isocirrus DA. ' Porcupine,' 1870. Enlarged. 



5. Lateral view of the cephalic region of Isocirrus planiceps, Sars, dredged off the 



Hebrides. Enlarged. 



5 a. Caudal disc. Enlarged. 



5 b. Snout of variety G. Skerries, Shetland, 1868. Seen from the ventral surface. 



This is not mentioned in the text. Enlarged. 



6. Lateral view of the cephalic region of Arwidssonia zetlandica, Mel. Enlarged. 



6 a. Another example with the proboscis extruded. Enlarged. 

 6 b. Papillas of the proboscis. Magnified. 



6 c. Dorsal view of the cephalic plate of the same. Enlarged. 



6 d. Ventral view of the cephalic plate with the mouth. Enlarged. 



6 e. View of the caudal disc. Enlarged. 

 6f. Lateral view of the same. Enlarged. 



7 and 7 a. Dorsal and lateral views of Praxillura 0. ' Porcupine,' 1870. x 15. 

 8. Segments of Bhodine gracilior from Norway showing the collars. 



