144 BALANTD^E. 



as many ducts and glands as there are discs of membrane, 

 all adhering together. In on*e specimen, it appeared that 

 normally there were four sets of cement-ducts, as in the 

 allied genera of Coronula and Platylepas; but in other 

 specimens, the ducts were distributed very irregularly. In 

 one case the two cement-trunks extended parallel and close 

 together, one of them terminating long before the other. I 

 have given a figure (PI. 28, fig. 3) of three of the cement- 

 glands, removed from the basal membrane, together with their 

 ducts. The cement-trunk (//) seemed to be a little enlarged, 

 and to be crossed by septa, as it entered the glands (h) t but I 

 could not make out this structure clearly enough to be repre- 

 sented. Whilst young, the cement-glands stand some little 

 way apart from each other ; and in the figure given of some 

 of the last-formed glands, they are hardly separate enough. 

 Each gland gives out obliquely, on one side, a cement-duct (c) 

 which I traced in several cases to the margin of one of the 

 discs of basal membrane, where cement issued from it ; and 

 on the opposite side, a tapering spur (b), varying in length, 

 which may be called, and I believe really is, a rudimentary 

 duct. Of these spurs we shall meet many instances in 

 other genera. The duct (c) and the spur (It), close to 

 where they entered the gland, in some specimens gave off, at 

 about right angles, short blunt points, or rudimentary 

 branches. This duct and spur correspond, I 'believe, 

 w T ith the two ducts in Coronula ; but besides these, a 

 duct (a) is given off from one end of the gland, from the 

 surface opposite to that at which the cement-trunk enters. 

 This duct (a) is very singular, from always forming a loop 

 (a), with two spurs projecting from it : these two spurs 

 occasionally spring from a common point : I have seen 

 nothing like this structure in any other Cirripede. This 

 duct (a) runs, like the duct (c), to the margin of its own disc 

 of basal membrane, where it debouches. Besides these ducts, 

 in the best specimen which I examined, there were two 

 other sets of ducts, which were slightly zig-zag, and at each 

 angular bend, a mere knob or point, or at most a short 

 branch, was given off; but this branch seemed never to run 

 to the margin of the basal membrane or to give out cement ; 

 whereas the main branch did give out cement. I was 



