Dr. F. Miiller on Balanus armatus. 395 
about a fathom below the level of the water at midtide, on an 
isolated rock (not far from the shore at the south end of the 
Praia de Fora), and forms dense, slightly branched bushes of 
as much as 0°15 metre in height. The flesh-coloured stem of 
this polype, about 2 millims. in thickness, is usually coated 
by a dark-yellow sponge with pin-like siliceous spicules, form- 
ing a thin crust; and Balanus armatus is rarely absent from 
such sponge-coated polyparies: as many as ten or twelve are 
frequently seated, closely pressed together, upon such a poly- 
pary ; and these are likewise covered by the sponge up to the 
opening. 
On the same rock four other Balanidee reside :—uppermost, 
above midwater, Chthamalus stellatus; at the lower limit of 
this species, and usually closely covered by it, Zetraclita po- 
rosa, especially on the seaward side; a little lower are seated 
some large shells of Balanus tintinnabulum; and then follows, 
extending down into the domain of the Carijoa, which is 
domiciled on the landward side of the rock, Balanus impro- 
visus, var. assimilis. The latter occurs also in single speci- 
mens seated on the Carzjoa and sometimes on Balanus armatus, 
or serving as a support for the latter. Once only I found a 
small B. tintinnabulum, only 8 millims. in height, upon the 
Carijoa. 
Sometimes, but rather rarely, B. armatus is found attached 
to rocks. On one occasion I found two of its shells, in com- 
pany with numerous specimens of B. improvisus, var. assimilis, 
upon a living Purpura. Lastly, I possess two specimens 
the same level: the greet majority of these remain short (about 4 millims. 
in un we and simple ; but some become elongated, and again put forth 
lateral branchlets, The branches and branchlets perfectly resemble the 
stem in their structure. Each of them bears a polype at its extremity, and 
is traversed by its body-cavity. The body-cavities of the individual po- 
lypes which, as stem, branches, and branchlets, compose the polypary, 
are not connected with each other. From the lower extremity oP the 
stem issue some thinner tubes, which act as roots, and, when applied to 
flat surfaces, are often flattened and dilated. Sometimes two neighbour- 
ing branches grow together superficially ; this takes place more frequently 
in the roots. en exposed to the light, the dried polypary is very ra- 
pidly and completely bleached. Even in the fresh state, individual poly- 
paries are almost colourless ; but others are, on the contrary, much darker 
than is shown in the figure. The name Carijoa is derived from that of 
the inhabitants of our island (Santa Catharina) at the time of its disco- 
very by Europeans,—the Carijés. 
Besides the yellow coat [mentioned in the text], four or five species of 
Reniera are found, but not very frequently, adhering to the Carijoa ; these 
are of a dark-red, pale-violet, greenish-grey, or snow-white colour; and 
one can imagine nothing of a gayer appearance than a bush of Carijoa 
such as I have seen, traversed and enveloped by all these sponges at the 
same time. 
28* 
