HIPPURELLA. 35 
Another feature in which Anfennopsis hippuris differs from the species 
of Antennularia consists in the absence of the tow-like mass of fila- 
ments which forms the hydrorhiza of the various species hitherto referred 
to the latter genus, the place of these entangled filaments being here 
taken by a small knot of free tubular fibres. 
Antennopsis hippuris. 
Pi. XXI. Figs. 3, 6. 
Trophosome. — Hydrocaulus attaining a height of about two inches, spring- 
ing from a cluster of distinct tubular fibres; stem simple, non-fascicled, 
divided into rather short internodes; ramuli slender, supported each by 
a thick process of the rachis which is given off from all sides irreg- 
ularly, every alternate internode of the ramulus supporting a hydrotheca. 
Hydrothecz small, cup-shaped. Hydrothecal internodes carrying besides 
the supracalycine nematophores two mesial nematophores, one at the 
proximal and one at the distal side of the hydrothece; intervening 
internodes with two mesial nematophores. 
Gonosome. — Gonangia shortly pedunculate, borne singly in the axils 
of the ramuli; male? elongated oval, with an oblique terminal orifice ; 
female? slipper-shaped with the distal end curved over to one side, 
and with a sub-terminal orifice. 
Off Double-Headed Shot Key, from a depth of 195 fathoms. 
Antennopsis hippuris is a small and rather delicate species. Like almost 
every other hydroid, it is dioecious, and the collection contains specimens 
of each sex, which differ from one another considerably in the form of 
the gonangia. The contents of the gonangia were not well enough pre- 
served to enable their nature to be determined, and it is therefore with 
hesitation that, guided by the analogy of some other forms, I have 
regarded the long oval gonangia as male, and the shorter slipper-shaped 
ones as female. 
HIPPURELLA ALLMAN nov. gen. 
GeneRIC CHarActTerR. Trophosome. — Hydrocaulus branched, ultimate 
ramuli pinnate on the proximal portion of the branches, but distributed 
on all sides towards their distal extremities. Hydrothecz borne on the 
ultimate ramuli, unilateral, with entire margin, associated with a pair of 
