THE SPINED AND SLENDER PEDICELLINA. 217 



twitched inwards at the tips, in the same manner as 

 those of that genus. 



I find two other species of the same genus : the 

 one is P. echi?iata, much like the ahove in every 

 respect, except that the stalk is more or less studded 

 with thick bristles or prickles standing out at right 

 angles. The other is marked by a very slender stalk, 

 sometimes gently swollen in the middle, and having 

 its base abruptly enlarged into a bottle-shaped bulb. 

 The tentacles nearly meet in the centre of the disk. 

 (Plate XII. Fig. 5). This species chiefly occurs on 

 the common Coralline. I have little doubt that it is 

 the P. gracilis of Sars ; though I find the bulbous 

 base much more abruptly angular than in his figures; 

 my specimens also have fifteen tentacles, whereas 

 twenty are assigned to the species by this eminent 

 Norwegian zoologist. This character, however, 

 depends probably upon age rather than upon species. 



