492 MR. E. T. BROWNE ON [Mar. 17, 
reproductive organs form a small oval swelling about halfway 
down each of the four radial canals. In some of the specimens 
belonging to this stage the stomach is prolonged into the substance 
of the umbrella. The prolongation or apical stalk disappears in 
the later stages, but its presence indicates in some species that the 
medusa has not long been liberated from its hydroid.’ The mouth 
bas four small lips. 
2Qnd Stage. Light tentacles—The interradial tentacle-bulbs 
belonging to the first stage develop tentacles, and a few adradial 
tentacle-bulbs begin to appear. The marginal vesicles never exceed 
eight even in the adult form, but the otoliths show an increase in 
number. At this stage sometimes four otoliths may be present, 
but usually two or three. Width of the umbrella about 3 mm. 
and slightly less in height. 
3rd Stage. Sixteen tentacles—The adradial tentacles appear in 
no definite order, and when they reach nearly their full size other 
tentacle-bulbs commence to grow. The generative organs form a 
long oval patch upon the radial canals. The otoliths in each 
vesicle vary from two to four. Diameter of the umbrella 4 to 
5 mm. 
Adult Form. (Plate XVII. fig. 2.)—I place under this head all 
specimens with more than 16 tentacles. They increase in number 
until 32 is reached, but this number may not be the maximum, 
though it is the most I have seen in a specimen. The marginal 
vesicles always remain eight in number, one of the characteristic 
features of the species and by which it may be distinguished from 
Phialidium temporarium. The otoliths in the vesicles show con- 
siderable variation even in the same individual. Three or four 
appear to be about the usual number present but sometimes more. 
One specimen had five to eight otoliths. The umbrella becomes 
very thick especially at the aboral end. By the thickness of the 
umbrella I could usually recognize this species in an aquarium 
when in company with Phialidium temporarium. 
The generative cells, which in the earliest stage form a small 
oval patch about halfway down each radial canal, gradually grow 
downwards or outwards but do not touch the margin. Usually 
of a yellowish-brown colour. 
The largest specimen seen measured 13 mm. in width and 4 mm. 
in height. During my visit to Plymouth in September 1893 I 
saw several specimens of this medusa, belonging to the 1st and 2nd 
stages, and some early stages at Port Erin in May 1894. 
According to Haeckel this medusa, possessing only eight mar- 
ginal vesicles and no cirri, ought to be placed in the genus T%aropsis. 
But as the medusa is more like the species belonging to Phialidium 
than Tiaropsis, I prefer to place it temporarily in the genus Phia- 
lidium until its hydroid has been found, rather than make a new 
genus. 
Evrima insienis (Keferstein). 
Siphonorhynchus insignis, Keferstein (1862), 
