444 THE DEPTHS OF THE SEA. [CHAP. ix. 



mud, took about twenty specimens of a handsome 

 Pentacrinus involved in the ' hempen tangles ; ' and 

 this splendid addition to the fauna of the European 

 seas my friend has done me the honour to associate 

 with my name. 



Pentacrinus wyville-thomsoni, JEFFREYS (Pig. 71), 

 is intermediate in some of its characters between P. 

 asteria and P. mulleri; it approaches the latter species, 

 however, the more nearly. In a mature specimen the 

 stem is about 120 mm. in length, and consists of five 

 or six internodes. The whorls of cirri towards the 

 lower part of the stem are 40 ram. apart, and the in- 

 ternodes contain from thirty to thirty-five joints. The 

 cirri are rather short and stand straight out from the 

 nodal joint, or curve sharply downwards, as in P. 

 asteria. The nodal joint is single, and the syzygy 

 separates it from the joint immediately beneath it, 

 which does not differ materially from the ordinary 

 internodal stem-joint. All the stems of mature 

 examples of this species end uniformly in a nodal 

 joint, surrounded with its whorl of cirri, which curve 

 downwards into a kind of grappling root. The lower 

 surface of the terminal joint is in all smoothed and 

 rounded, evidently by absorption, showing that the 

 animal had for long been free. This character I 

 have remarked as occurring in some specimens of 

 P. mulleri. I have no doubt that it is constant in 

 the present species, and that the animal lives loosely 

 rooted in the soft mud, and can change its place at 

 pleasure by swimming with its pinnated arms ; that 

 it is in fact intermediate in this respect between 

 the free genus Antedon and the permanently fixed 

 crinoids. 



