REMARKABLE MARINE INVERTEBRATA NEW TO THE BRITISH SEAS. 311 






































: - simple; no conspicuous genital glands; two long marginal tentacles, and 
_ numerous intermediate rudimentary tubercles, all with ocelli at their bases ; 
stomach at the end of a very long, extensile, cylindrical tubular proboscidiform 
peduncle, with a simple or obscurely lobed orifice. 
We have deemed it necessary to constitute this genus for a very curious little 
naked-eyed medusa of the family Sarsiad@, so distinct in its characters, as not 
to be referable to any of the defined groups. We have dedicated it to Janus 
Puancus, who, in his tract “ De Conchis Minus Notis,” published in 1739, was 
the first naturalist who figured a naked-eyed medusa. 
Plancia gracilis. Sp. Nov.—Disk hemispherical, depressed, colourless, 
smooth, its margin furnished with two long tubular tentacula, one on each side 
opposite the terminations of gastrovascular canals; at the origin of each of these 
is asmall fixed tentacular process, connecting the umbrella with the subumbrella, 
as in the genus Sieenstrupia. The remainder of the margin is occupied by about 
sixty minute tubercles or rudimentary tentacula, beside each of which on an 
oblong process is a minute black ocellus. Four simple gastrovascular canals, 
connected with a marginal canal, divide the disk into as many equal segments. 
The entrance of the cavity is protected by a broad veil. The peduncle is very 
long and extensile, resembling in shape that of Sarsia; it is very acute at its 
base, and is of a general pink hue, with darker lines, as if of genital glands lining 
its tube. It is terminated by a short orange-coloured campanulate stomach, 
opening by an irregularly four-lobed orifice. 
This is an active and elegant little creature. Its disk measures rather less 
than a quarter of an inch across. When swimming, it carries its two tentacula 
streaming behind it for a great length. We procured several examples in the 
- Sound of Mull and off Staffa. 
Oceania ducalis. Sp. Nov.—Umbrella campanulate, subglobose, round above, 
smooth, colourless, transparent. Subumbrella rather small in proportion, its 
_ orifice protected by a conspicuous veil; its margin edged with rose-colour, and 
bearing 16 (3 x 4+ 4) pinkish tentacula, springing from bulbous bases, each of 
__ which is marked by a conspicuous crimson or purple crescentic ocellus: between 
each pair of tentacles is a minute tubercular process. Down the sides of the 
_ subumbrella run the four simple gastrovascular canals, tinged with red. From 
_ its centre depends the oblong, massive, reddish-tawny peduncle, in the upper part 
_ of which are obscurely seen the convoluted reproductive glands. The orifice of - 
_ the peduncle is campanulate, and bordered by four slightly-fimbriated lips. The 
height of the body is less than a quarter of an inch. 
: It was taken at Tobermory. We had previously met with the same species 
on the coast of Dorsetshire. 
Slabberia catenata.—Hitherto only a single species of the genus-Slabberia, one 
of the most curious types of the Medusa Gymnopthalmata, has been met with, 
VOL. XX. PART II. ae 
