728 EDWAKU T. BROWNE. 



had four unbranched radiating canals and four tentacles; but it is probable that they would 

 assume the form of the parent stock after development." 



With the aid of the figures I have been able to draw up a description of the species and 

 by bestowing upon it a specific name may prevent it from becoming lost again. 



Description. Umbrella hemispherical, with a slight apical projection. Stomach short. 

 Four main radial canals, each with three branches, all going to the margin of the umbrella. 

 A stolon bearing medusa-buds hangs from each main canal at its junction with its first branch, 

 and has at the free end a cluster of nematocysts. Sixteen short marginal tentacles, in direct 

 communication with the radial canals. Size and colour not recorded. 



Distribution. Tropical Pacific: Australasia; Louisiade Islands (Huxley). 



Prohoscidactyla varians, species nova (PI. LIV. figs. 1, 2). 



The collection contains only a single specimen, and though in a good state of preservation, 

 yet it is badly contracted and has lost its natural shape. It is regarded by me as an abnormal 

 specimen. 



Description. Umbrella a little broader than high. Stomach with six lobes. Six radial 

 canals, each with one to three lateral branches. Circular canal absent. Medusa-buds upon 

 the radial canals, close to the stomach. Sixteen or more tentacles, with large triangular basal 

 bulbs. Clusters of nematocysts on the ex-umbrella, arranged in radial rows. 



Colour. Basal bulbs of the tentacles dark bro\vn (in formalin). 



Size. Umbrella 3 mm. in width and 2 mm. in length. 



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



If this solitary specimen had possessed no medusa-buds I should have placed it in the 

 genus Willia, on account of its possessing six main radial canals. The medusa-buds show 

 only four basal bulbs, with tentacles just beginning to develop, and there is not the slightest 

 trace of any more bulbs. The fully developed medusa-buds of Prohoscidactyla tropica and 

 gemvufera have four main radial canals and four tentacles. The earliest free-swimming stage 

 of Prohoscidactyla ornata has also four main radial canals and four tentacles. But the earliest 

 stage of Willia stellata has six main canals and six tentacles. The medusa-buds of this 

 specimen indicate that it belongs to the genus Prohoscidactyla and not to the genus Willia. 



The parent medusa has six main radial canals with a variable number of lateral branches, 

 and the lobes of the stomach show a want of symmetry. Willia stellata frequently shows 

 a variation in the number of radial canals and in the number of lateral branches. As a 

 rule when the number of main canals is above the normal number, then the branching of 

 the canals is irregular. It will be seen in the figure that the abnormality of this specimen 

 occurs in one quadrant, where three adjacent canals leave the stomach, each having only one 

 lateral branch. These occupy the place of a main canal with four terminations on the margin 

 of the umbrella. In a normal specimen at this stage, I consider that there should be a 

 stomach with four lobes, four main radial canals, each twice dichotomously branched, sixteen 

 tentacles. The specimen has only two medusa-buds, each of which is situated on a main radial 

 canal, adjacent to the stomach. There is no stolon with a series of medusa-buds as found in 

 P. tropica and P. gemmifera. The basal bulbs of the tentacles (fig. 2) are large and extend 



