572 ORDER ABDOMINALIA. 



somewhat conical, projecting month, which is separated on 

 the ventral surface from the rest of the body by a distinct 

 fold or articulation, where the muscles proceeding to the above 

 gnathites are attached. The labrnm (<?, fig. 5, 9) is of large 

 size ; and the crest close over the opening of the oesophagus 

 is produced into a great, lancet-shaped, moveable organ, 

 wholly unlike anything occurring in any other cirripede : 

 it is coloured purple, and is thickly fringed in the upper part 

 by very fine hairs : it is bowed a little backwards from the 

 mouth : the base, which rather overhangs the oesophagus, 

 is a little contracted, and is transversely marked by an 

 articulation : two small, parallel, voluntary muscles (with 

 transverse striae) are attached at their lower ends close 

 beneath the articulation, and extend about one third up the 

 organ : their contraction would serve to erect it ; and their 

 relaxation would, apparently, allow it to fall backwards on 

 a little knob (<?', fig. 5) behind. This little knob resembles 

 a similar projection in many of the Lepadidse. As the 

 labrum is formed of similar membrane with that of the suc- 

 ceeding segment of the body, its limit downward, beneath 

 the knob, can be told only by a small apodeme which pro- 

 jects inwards, at a little distance within the line where the 

 membrane of the body is reflexed upwards (c), so as to form 

 the inner tunic of the sack. 



The mandibles, palpi, and maxillae, all project more than 

 is usual. The Palpi (/, fig. 9, 5) are narrow, flattened, and 

 taper a little ; they support a few long bristles on their tips, 

 and on one of their sides. In every other cirripede (in which 

 the palpi are developed) they are directed transversely across 

 the mouth, one towards the other, and are for a considerable 

 space united to the labrum : here they project straight up, 

 and seem to rise exteriorly to the bases of the mandibles ; 

 they are, however, united to the basal lateral edges of the 

 labrum, and when the latter is torn from the rest of the 

 mouth, the palpi separate with it. I could nut distinguish 

 the knob on which, in every other cirripede, the palpi are 

 articulated. The Mandibles (fig. 8) have an upper, lower, 

 and middle tooth, with some finer intermediate points and 

 hairs. The Maxilla* (fig. 7) are narrowed in at their spinose 

 edge, where there are three large spines and several finer 



