60 
THE VOYAGE OF H.M.S. CHALLENGER. 
from its hydrorhizal end has a height of four inches. From the main stem, which is 
simple, are emitted alternate pinnae, which are themselves occasionally branched. The 
hydrothecae are absolutely cylindrical, and arise close to the distal ends of the internodes. 
They have but a very small portion of their epicauline side adnate to the internode, and 
from the fact of this portion being nearly in the same plane with the true base the 
hydrothecse have the appearance of being entirely free from the base to the summit. 
That the attached portion, however, must be regarded as consisting not only of the true 
base but of a portion of the epicauline side, will be apparent from a comparison with such 
species as Sertularia echinocarpa and Sertularia geniculata (PI. XXVIII.), and it will 
thus be seen that the present species offers no real exception to the general character of 
the family. The four-cusped margin of the hydrotheca distinguishes this species from 
Sertularia integritheca, which it closely resembles in almost every other respect, and 
with which it was associated in the contents of the dredge. 
Sertularia integritheca, n. sp. (PI. XXIX. figs. 2, 2a). 
Trophosome. — Hydrocaulus consisting of unbranched, monosiphonic stems, set with 
pinnately disposed alternate ramuli. Hydrothecae borne both by stems and ramuli, 
one on every internode, alternate, exactly cylindrical, each springing from the 
hydrocaulus by its base, and then free for nearly its entire height, orifice circular and 
entire. 
Gonosome not present. 
Locality. — Off Bahia. 
Sertularia integra is a large and strong-growing species, chiefly characterised by its 
absolutely cylindrical hydrothecae, whose perfectly circular and entire orifice occupies the 
whole summit of the hydrotheca. 
The stems spring at intervals from a creeping, tubular filament, and attain a height 
of about four inches. They are rather thick, monosiphonic throughout, not dividing into 
branches, but set along nearly their entire length with alternate pinnae. 
The hydrothecae are each attached to the hydrocaulus by its base and by a very 
small extent of the epicauline side. In this character they entirely agree with the 
preceding species [Sertularia cylindritheca). The joints which separate the internodes 
occur just above the hydrothecae. They are sufficiently distinct towards the distal ends 
of the ramuli, but in the more proximal or older parts they frequently become indistinct 
or even obliterated. 
The species is a member of the rich Hydroid fauna of Bahia, but though the 
specimens obtained were finely developed they were quite destitute of gonosome. 
