REPORT ON THE HYDROIDA. 
59 
Sertularia geniculcita, n. sp. (PL XXVIII. figs. 3, 3a, 36). 
Trophosome. — Stem monosiphonic, very slender and hyaline, irregularly branched, 
internodes very long, inclined to one another at a vide angle so as to give a geniculate 
form to the stem. Hydrothecse alternate, borne close to the distal ends of the 
internodes, to which they are aclnate by about one-third of their epicauline side, very 
deep, tumid towards the base, and thence gradually narrowing and becoming cylindrical 
towards the summit, which is occupied by the quadrilateral orifice. 
Gonosome. — Gonangia obovate, with truncated summit, springing by a narrow 
proximal end from a point on the internode just below the base of a hydrotheca. 
Locality. — Station 214, south of the Philippines ; lat. 4° 33' N., long. 127° 6' E.; 
depth, 500 fathoms. 
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Sertularia geniculata is a very slender, perfectly hyaline form. The collection 
contains but a single example, which is less than an inch in height, but as the specimen 
is fragmentary and has lost its hydrorhizal extremity, no assertion can be made as to the 
height which the species may naturally attain. It is probable, however, that the perfect 
colony does not much exceed in size the portion which has been preserved. 
The internodes, which are nearly twice as long as the very deep, narrow hydrothecse, 
become wider towards their distal ends, thus adding to the knee-like form of the joints. 
The hydrothecse, for some distance below the orifice, are marked by parallel, 
transverse strise, and the orifice itself is crowned by an exceedingly delicate, four-valved, 
membranous operculum, so delicate indeed that it was only in a few of the hydrothecse 
that it was sufficiently well preserved to allow of demonstration. 
Just within the orifice may be seen in optical section two broad, conical projections 
of the chitinous walls, one on the epicauline, and the other on the apocauline side of the 
hydrotheca. It is not improbable that in the living animal they give attachment to 
contractile bands employed in the closing of the operculum. 
Sertularia cylindritheca, n. sp. (PL XXIX. figs. 1, la). 
Trophosome. — Main stem monosiphonic, not divided into branches, but set with 
pinnately disposed, alternate ramuli. Hydrothecse borne both by stem and pinnse, one 
only on every internode, alternate, cylindrical, adnate by the base to the hydrocaulus, 
and free for nearly the whole of their epicauline side, margin with four low cusps. 
Gonosome not present. 
Locality. — Off Bahia. 
Sertularia cylindritheca, though destitute of fasciculation, is a strong-growing, rather 
rigid form. The specimen in the collection is fragmentary, and though broken away 
