HYDROMEDTJSAE. 731 



numerical change was the sign of a variation from the normal type. The British Eucopidae 

 very rarely show a nuinerical variation in the radial canals. There can be but little doubt 

 that this pentamerous species has arisen from a Phialidium-\ike medusa, which had four radial 

 canals, four gonads, and a mouth with four lips. 



In the Maldive collection there are two specimens belonging to the Eucopidae, with five 

 radial canals. If Mayer had not instituted the genus Pseudocli/tia, the species would have 

 been placed in the genus Phiaiidium and regarded as a variation from the normal type. 

 I think, on the whole, it will be best to place this new species in the genus Pseudoclytia. 

 The two specimens are practically identical, and the chances of catching two abnormal 

 Phiaiidium exactly alike are very remote so far as in}' experience goes. 



Pseudoclytia gardineri, species nova. (PI. LV. figs. 1 — 3.) 



Description of the Species. Umbrella broader than high ( ? watch-glass-shaped). Stomach 

 short with a pentagonal base. Mouth with five small lips. Five radial canals (four nearly at 

 right angles and one in between). Gonads veiy small (globular in the female and oval in 

 the male), one situated on each radial canal about midway between the stomach and the 

 margin. About 13 — 14 tentacles, with globular basal bulbs. Usually one or two marginal 

 bulbs between every two tentacles, except in one segment where there is a conspicuous group 

 of six bulbs (three on each side of a tentacle). Sense oi-gans numerous, usually two or three 

 between every two tentacles, with probably one otolith. 



Size. Diameter of the umbrella about .5 mm. 



Distribution. Indian Ocean; Maldive Islands, Miladumadulu (Gardiner). 



Neither of the specimens is in very good condition, so that the exact shape of the 

 umbrella is doubtful, but it seems fairly thin and without a thick mass of jelly over the 

 cavity of the umbrella. The mouth of one specimen is closed, and it has five distinct lips ; 

 in the other specimen it is expanded and has a quadrangular aperture with a sinuous margin. 

 The ovaries are very small, globular in shape and containing about four to six ova. The 

 gonads of the male are a little nearer the margin of the umbrella than those of the female. 

 The characteristic feature of this species and that upon which the specific character is based 

 is the group of six large marginal bulbs adjacent to one of the tentacles. This gi'oup is 

 very conspicuous on the margin of the umbrella and is at once seen. The tentacle is in 

 the centre of the group (fig. 3), and has three bulbs on each side. A marginal sense organ 

 lies between each of the outer two bulbs, but there is not one next the tentacle. On the 

 inner side of the circular canal a series of bays exists, corresponding in position to the bulbs 

 and tentacles. In the male specimen (fig. 1) there are indications of two more groups of 

 bulbs being formed, each with two bulbs on either side of a tentacle. 



It is a pleasure to me to associate this new species with the name of Mr J. Stanley 

 Gardiner. 



Family Aequoridae, Eschscholtz, 1829. 



Genus Aequorea, Peron et Lesueur, 1809. 



Generic Character. Aequoridae with numerous simple unbranched radial canals. Stomach 

 circular, with the lower wall fully developed. Mouth capable of closing up. 



G. II. 94 



