belonging to a new Order of the Class Cirripedia. 311 



are three pairs of natatory legs placed well forwards and indi- 

 stinctly articulated ; the anterior pair are simple and furnished 

 with a few long seta3 at their extremities ; the other two pairs are 

 bifid, the anterior portion being much the stouter, and marked 

 with several indistinct close-set articulations towards the extre- 

 mity ; each articulation bearing on its posterior margin a long 

 seta : the posterior branch of the limb is also furnished with setae 

 at its extremity. On each side of the head there is a stout pro- 

 cess a little arched backwards with the point obtuse ; these I am 

 inclined to look upon as antennae, for they appear to arise from 

 the head beneath the shield, though this could not be determined 

 with certainty. It is possible enough that they are lateral pro- 

 longations of the shield, similar to the '^ anterior horns " of the 

 larva of the pedunculate Cirripedes. Whether so or not, the 

 larva of this new animal may at once be distinguished from that 

 of this division of the Barnacles by the absence of the long spine 

 projecting from the posterior margin of the shield. In other 

 respects it evidently shows a strong general resemblance to the 

 larva of these animals. 



The larva, then, as well as the characters of the animal itself, 

 proves it to be a true Cirripede, while, in the former, we see a 

 confirmation of the relationship shown by Thompson to exist 

 between these creatures and the Crustaceans. Indeed this ani- 

 mal in several particulars exhibits a very close approximation to 

 them. The shape of the arms or palps by the sides of the mouth 

 resembles not a little the mandibles of the Nymphons or the ante- 

 rior feet of some of the higher forms ; and the horny shield over- 

 lying the expanded portion of the animal gives somewhat the 

 idea of a rudimentary carapace : the rostrated upper lip, too, and 

 setaceous branchiae have likewise a very crustacean appearance. 



In these particulars our new animal differs from the typical 

 Cirripedes ; but not more than in general form, which is very 

 unlike that of either of the two great divisions of the class. The 

 prehensile arms or feet, too, are highly characteristic in this, 

 having, in fact, more the appearance of true feet than the cirri of 

 the other Cirripedes ; there are only six, or three pairs, while in 

 all the other Barnacles there are double that number, or six pairs. 

 In our animal the last or terminal joint is shortest and is simple, 

 having few and comparatively short setse : the arms or feet indeed 

 appear to be merely prehensile organs laying hold of prey by the 

 aid of the cushion-like swellings before described as attached to 

 their inner margins. 



The cirrigerous feet of the other Cirripedes are also undoubt- 

 edly prehensile, but in a very different manner. In these each 

 terminates in a pair of slender, much-elongated and curled cirri 

 composed of numerous, minute articulations, furnished with a 



