678 ON CRUSTACEA BROUGHT BY DR WILLEY FROM THE SOUTH SEAS. 



and extend itself slowly again.' The notes on colour will be given in the course of 

 the general description. 



The adherent disk is oval, with the narrower end towards the capitulum. On the 

 upper surface its skin appears to be smooth, but roughened on the lower adhesive 

 side. Between the two surfaces there is a pulpy mass containing numerous short 

 muscles. Over the peduncle, however, the sheath forms only a thin transparent skin, 

 and on the side next the shell this seems to be wanting or else of extreme tenuit\^ 

 The colour of the disk in life is described as light reddish brown, a thin red line 

 (nigrescent in spirit) running round the translucent part which covers the base of the 

 peduncle, which itself is faintly roseate in life (greyish in spirit). On the under 

 surface, though the boundary between disk and peduncle is strongly marked, laterally 

 by separation and apically where they meet by colouring, yet the longitudinal muscles of 

 the peduncle run without flexure or any sort of interruption through the coloured band 

 into the disk. 



The capitulum is distinguished from the peduncle by a slightly greater thickness 

 and by its rigidity, these characters being obviously due to its containing the chief 

 mass of the animal's body. The hue in life may be gathered from its description 

 as a white mass with a deep chocolate-bro^\^l band at its base. It is not quite 

 cylindrical, being laterally somewhat compressed and becoming distally carinate with a 

 pellucid, crest-like border, which overarches the fissure-like orifice. The sides of the 

 fissure close tightly together, not meeting edge to edge but with lateral compression. 

 They rest at the base upon a projecting bulb, and appear to be comparable wth the 

 corresponding part of Alcippe lampas, in which, however, there are two sharp projections 

 at the base, instead of a single bulb. Of this latter the function may be to give some 

 support to the long first cirri when protruded. 



The upper lip or labrum has the free margin rather deeply concave, and fringed 

 with forty-six denticles. From the rounded angles two rows of fine hairs converge 

 backward on the surface. It has points of resemblance to the corresponding appendage 

 in Eremolepas pellucida (Aurivillius) and to that in Alcippe lampas, but the bullate 

 or swollen part extending beyond the transverse crest escaped m}' observation, perhaps 

 throuo-h a mishap in the dissection, rather than from the absence of a feature said 

 by Darwin to be common to all the Lepadidae. It is not shown in the figure of 

 the labrum of E. pellucida by Aurivillius. 



The palps are firmly connected with the labrum, the free lobe of each projecting 

 in advance of or beside the rounded angle of the labrum, and having the forward 

 margin fringed with seta-like spines, as also the inner margin for half the depth, 

 behind which the lobe is emarginate. These ' palps,' though attached to the labrum, 

 are regarded as really palps of the mandibles. One may suppose that from the 

 extreme compression of the mouth-organs in the cirripedes there has resulted an 

 anastomosis between labrum and mandibles which has ended in the mandibular palp 

 havino a firmer attachment to the labrum than to its own stock. (See Darwin, 

 Balauidae, pp. 75, 78.) 



The mandibles are rather peculiar. The upper tooth and the longer lower tooth 

 of the cutting edge are as usual acute, but the two intermediate processes are convex 



