HIPPURELLA. 35 



Another feature in which Antennopsis 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. 

 PL XXL 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. 

 Hydrothecae 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 hydrothecte ; 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. 



09' 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 Character. Trophosome. — Hydrocaulus branched, ultimate 

 ramuli pinnate on the proximal portion of the branches, but distributed 

 on all sides towards their distal extremities. Hydrothecae borne on the 

 ultimate ramuli, unilateral, with entire margin, associated with a pair of 



