THE ANATOMY OF ALCYONIUM DTGITATUM. 359 



Koch (21) says, "The tentacles possess twelve to fourteen pairs 

 of pinnse (Fiederpaare)." In our English species it is quite 

 impossible to recognise the pinnae as pairs. Not only do we 

 find an uneven number of pinnse on the two sides of many of 

 the tentacles, but a minute examination of the free end of the 

 tentacle usually shows a small pinna on one side without any 

 corresponding one on the other (see fig. 10). 



Carl Vogt and Jung's description (37) of the tentacles is as 

 follows : — " Bei massiger Ausdehnung bieten sie die Form 

 langen Blumenblatter mit sageformigen Randern, aber in 

 gewissen Fallen verlangern sich alle Theile dermaassen, dass 

 die Fiihler Hirsclihornern ahneln, welche auf beiden Seiten 

 mit sehr langen Zacken besetzt sind." 



I have never seen this " antler " appearance of the tentacles 

 except in spirit specimens, and I am inclined to think it is 

 entirely due to the action of the preservative fluid, for in life 

 the tentacles appear to be perfectly regular (fig. 11). 



The tentacles of fully expanded polyps when examined alive 

 with a low power of the microscope vary very considerably in 

 appearance. In PI. 37, fig. 11, I have drawn the crown 

 of a polyp I observed in a recently caught specimen which 

 expanded in the bucket of sea water in which it was placed 

 immediately after its removal from the sea. The tentacles were 

 extremely extended, and at the base of each of them there was 

 a bullate swelling, on the side of which there were no pinnae. 

 From time to time a sudden and simultaneous movement of 

 contraction would occur, caused perhaps by a slight shaking of 

 the table, and the tentacles would assume a more or less rigid 

 appearance, with the bullate portion very much extended, but 

 the terminal portions and the pinnse very considerably short- 

 ened (fig. 6). These contractions lasted only a few seconds, 

 and then the tentacles extended themselves again and resumed 

 the condition represented in fig. 11. 



It is but rarely, however, that it is possible to observe the 

 polyps so fully extended as this. A condition such as that 

 figured in fig. 10, in which there is apparently no bullate por- 

 tion, is not unfrequently seen, and it is quite possible to kill a 



VOL. 37, PART 4. — NEW SEE. B B 



