86 
THE VOYAGE OF H.M.S. CHALLENGES. 
When articulated the internodes are connected either by short straight tubes, or with 
the intervention of a convoluted knot of slender tubules. 
The recent species of this genus, as above defined, with which I am acquainted, are 
about fifteen to seventeen in number, and they admit of being conveniently and more 
or less naturally grouped as under : — 
a. simplices. — In which the zoarium is simple, or composed, as it may be said, of a 
single segment, from which, however, loosely connected offsets sometimes spring 
irregularly, attached to the parent stock either by ordinary clasping filaments, or 
sometimes by a single, rather long tube arising from the front of a zocecium, when the 
young offset or branch may be regarded as homologous with the chitinous tubes resembling 
radical fibres presented in several species, which spring in a similar manner from the 
front or other part of a cell in other species of Salicornaria, as, notably, Salicornarict 
pilosa, Kirch., and Salicornaria bicornis, Bk., as well also as in many other species 
belonging to several genera. The only species in which this condition is very distinctly 
shown is Salicornaria clavata, n. sp.; there is, however, a small form from the Adriatic, 
termed by M. Costa Salicornaria gracilis, but which seems to me to be distinct, in 
which the same habit would appear to be present. 
(3. articulates. — In which the internodes are connected by elastic or flexible joints, 
and always arise in pairs, so as to constitute a dichotomous growth. These forms may 
again be subdivided into — (a), those in which the bond of union between .the segments 
consists of more or less numerous, short, thick-walled, chitinous tubes which are continuous 
at either end with the delicate endocyst of the terminal cells in the superior and inferior 
internodes ; and ( b ), those in which the connection is effected with the intervention of 
what Prof. Smitt terms a “ knot of intricated radical tubes.” The precise mode of connec- 
tion between this “ knot ” and the three internodes between which it forms the bond of 
union, I have not been able satisfactorily to determine, but so far as I can perceive one 
or two tubes arise from the summit of the inferior internode, and form an intricate 
plexus, which is lodged between the two superior segments, and gives off a single tubule 
to each. The junction, consequently, so far as the chitinous element is concerned, 
appears to be slight, though highly elastic. In most of the species thus furnished it 
should, moreover, be remarked that the calcareous walls of the contiguous internodes 
above and below are very closely applied to each other, so as to appear continuous, but 
I have not met with any case in which they are really so. The species belonging to 
this category are much more numerous than those in the other, and for the most part 
apparently confined to the southern hemisphere, the only apparent exception to this 
being Salicornaria johnsoni, which occurs also in the northern. 
It is worthy of remark that this difference in the manner of articulation appears to be 
connected with other characters distinctive of the respective groups. 
