146 BALANID/E. 



a view of a considerable portion of the basal membrane, 

 especially towards the circumference, some parallelism in 

 the branches could be perceived; one set of branches tending 

 to run in the direction of the ray of the circle, and the other 

 set in the line of the circumference. 



Elminius Kingii. — The cement-glands here resemble 

 those of Chelonobia, but the trunk does not seem to be 

 enlarged before entering the gland. The glands are 

 situated rather far apart ; and the chief peculiarity is, that 

 the trunk connecting the glands is as tortuous as the track 

 of a worm. Each gland gives out two ducts, which bifur- 

 cate repeatedly, and often inosculate, making, in parts, an 

 hexagonal mesh-work : some of the branches do not de- 

 bouch on the basal membrane, but terminate in blunt 

 points. So numerous are the ducts, that the basal mem- 

 brane may be compared to pieces of paper with the fine 

 fibrous branching roots of some plant dried and heaped on 

 it. Some of these ducts are very regularly jointed, and 

 resemble a conferva, — an appearance which I believe is 

 owing to divisions in the contained cement ; other ducts 

 are partially marked by little wrinkles, as presently to be 

 described under Balanus. The cement, instead of, as here- 

 tofore, invariably forming a slip round and beneath the cir- 

 cumference of the basal membrane, here often forms little, 

 independent, circular, and irregularly-shaped discs, each of 

 which has issued from a single orifice. I may here add 

 that in two species of Tetraclita I saw the cement-ducts 

 repeatedly bifurcating, with some of the branches inoscu- 

 lating, as in Elminius and Chelonobia. 



In Balanus balanoidcs, which, like all the Cirripedes 

 hitherto mentioned, has a membranous basis, I could only 

 make out an amazing number of bifurcating and inoscu- 

 lating cement-ducts, of very various diameters. The cement- 

 tissue, on the under side of the basal membrane, generally 

 consisted of little circular discs, on an average from |~ths 

 of an inch in diameter ; but there were also globules and 

 short tortuous threads of cement. In some very much 

 elongated and crowded specimens — in which, during the 

 downward growth of the walls, the basal membrane had 

 ceased to reach the surface of attachment, and being thus 



