192 IBLA CUMINGII 



than the long basal segment, from which it is divided 

 by a broad conspicuous articulation ; its lower surface 

 is flat and its upper convex, altogether resembling in shape 

 a mule's hoof ; its apex is fuzzy with the finest down ; 

 it bears a narrow ultimate segment, thrown, as usual, 

 on one side ; this segment supports on its rounded 

 irregular summit, at least five, I believe, judging from the 

 structure of the same part in the male larva of Ibla quadri- 

 valvis, six or seven spines, longer than the segment itself : 

 one long spine arises from the under side of the disc, 

 near the base of the ultimate segment, and points back- 

 ward : there is also a single curved spine on the outside, 

 near the distal end of the basal segment. These organs 

 were imbedded in a heart-shaped ball or cylinder of 

 brown, transparent, finely laminated cement, and thus 

 attached to the fibrous tissue of the female. The two 

 cement-ducts (fig. \f) were very plain, each about ^th of 

 an inch in diameter, containing the usual inner chord 

 of opaque cellular matter. I traced them at the one end 

 into the prehensile antennae as far as the disc ; and at the 

 other, up the peduncle for about one fourth of its length, 

 where I lost them, and could not discover with certainty 

 any cement glands. I may, however, here mention, that 

 I found in the lower half of the peduncle, numerous, 

 yellowish, transparent, excessively minute, pyramidal 

 bodies, with step-formed sides ; of these two or three 

 often cohered by their bases like crystals ; I have never 

 seen anything like these in other Cirripedes, but it has 

 occurred to me that they may possibly be connected with 

 the formation of the cement : for in the last larval con- 

 dition of Lepas, the cement-ducts run up to the gut- 

 formed ovaria, filled at this period with yellowish, grape- 

 like, cellular masses, without the intervention of cement 

 glands, and I can imagine that similar masses, not being 

 developed into functional ovaria, might give rise to the 

 yellow pyramidal bodies. 



Mouth. — The mouth is well developed ; it is repre- 

 sented as seen vertically from above, in PI. V, fig. 2, mag- 



