36 
THE YOYAGE OF IT.M.S. CHALLENGER. 
shortly peduncled hydrothecse. Hydrothecse borne both by the perisiphonic stem and 
the monosiphonic ramuli, deep and narrow, with the axis slightly curved away from 
the supporting ramulus or stem ; margin scarcely everted, peduncle formed of two short 
annular segments. 
Gonosome not present. 
Locality. — Off Somerset, Cape York, Torres Strait; depth, 8 to 12 fathoms. 
The deep narrow hydrothecse of the present species resemble in form those of a 
Lafoea, from which, however, they differ in the presence of the limiting diaphragm or 
floor at the basal end. The ramuli which carry the hydro thecae in two alternate series are 
here and there divided into internodes by transverse joints. These occur chiefly towards 
the distal extremity of the ramulus, where two hydrothecae usually intervene between 
two joints. The ramuli are very regularly disposed, forming a series of equidistant 
alternate pinnae on each side of the fascicled stem. Those of one side, however, are not 
placed exactly opposite to the middle points between the pinnae of the opposite side. 
I have little hesitation in regarding the present Hydroid, notwithstanding its more 
robust habit and somewhat more irregular ramification, as specifically identical with 
Lafoea halecioides of the “ Porcupine ” collection, a species which, in accordance with the 
limitation of Lafoea here insisted on, must be removed from that genus and placed in the 
genus Lictorella, keeping in mind, however, that so long as the gonosome is unknown, no 
generic allocation can be regarded as otherwise than provisional. The removal from Lafoea 
is justified by the fact of the hydrothecse being provided with a definite floor instead 
of having their cavity, as in the true Lafoea, directly continuous with that of the 
hydrothecse. 
The specific identification of the Challenger Hydroid with that of the “ Porcupine ” 
is not without significance, when we bear in mind the widely separated localities and very 
different conditions under which the two were found. The specimens brought home by 
the “ Porcupine ” were dredged from the cold area which lies between Shetland and the 
Fseroe Islands, and from depths of 640 and 345 fathoms ; while those of the Challenger 
were dredged off Cape York, Torres Strait, from a depth of about 8 fathoms. 
Lictorella cyathifera, n. sp. (PI. XI. figs. 3, 3a). 
Trophosome. — Hydrocaulus pinnately branched ; stem and principal branches peri- 
siphonic, becoming monosiphonic towards their extremities, and sending off very regular, 
pinnately disposed, alternate monosiphonic ramuli, which are destitute of distinct joints, and 
carry the pinnately disposed alternate hydrothecse. Hydrothecse deeply cyathiform. with 
an entire and very slightly everted rim, and supported on a very short unjointed peduncle 
which springs from a short fixed process of the hydrocaulus. 
Gonosome not known. 
