with the general surface of the membrane,--these being the intersected or worn down footstalks, with every trace of the calcareous beads gone. But in this same specimen, under the old peduncular membrane, there was a new one, studded with the usual circular calcareous beads, slightly unequal in size, generally about 1/400th of an inch in diameter, and each furnished with a tubulus; but as yet none of the star-headed points of chitine had been formed. I believe that these latter are developed from the tubuli leading to the calcified beads, and, therefore, are formed directly under them. In _L. cauta_ the lowest scales on the peduncle are a little larger than in _L. dorsalis_, giving a frosted appearance to it, and all of them are serrated (fig. 3 _d_) round their entire margins. Generally only the scales in the uppermost, or in the three or four upper rows are serrated, and this only on their arched and protuberant lower margins. The state of the serrated edge varies extremely in the same species, from elongated conical teeth to mere notches, according to the amount of wear and tear the individual has suffered since the last period of exuviation; so also do the teeth or serrated margins on the valves of the capitulum. Each scale has a fine tubulus passing from the corium through the membrane of the peduncle to its bluntly-pointed imbedded fang or base. The membrane is transparent, thin, and tender, to a degree I have not seen equalled in the other Lepadidæ, except, perhaps, in Ibla. It is much wrinkled transversely. _Muscles of the Peduncle._--These consist of the usual interior and longitudinal,--exterior and transverse--and oblique fasciæ; the former are unusually strong; downwards they are attached to the basal calcareous cup or disc, and upwards they extend all round to the lower curved margins of the valves. They are, as usual, without transverse striæ. Besides these, there are, (at least in _L. dorsalis_ and _L. Nicobarica_,) two little fans of striæ-less muscles, which occur in no other pedunculated cirripede; they are attached on each side of the central line of the carina, near its base; they extend transversely and a little upwards, and each fan converges to a point where the lower margins of the carina and terga touch; of these muscles, the upper fasciæ are the longest. Their action, I conceive, must be either to draw slightly together the basal points of the terga, and so serve to open their occludent margins, or to draw inwards the base of the carina: these muscles apparently first shadow forth the posterior or carinal, transversely-striated, opercular muscles of sessile cirripedes.