1896.] BRITISH HYDROIDS AND MEDUS2. 487 
Mitrocomella polydiadema (Romanes) is very much like Huchilota 
pilosella to the naked eye; but it has sixteen marginal vesicles 
and no cirri upon the ex-umbrella. 
Disrrizution. Scotland—Shetland Islands, Forbes. 
England—Plymouth, Garstang, Allen. Falmouth, Alder. 
Treland—Valencia Island, £. T. B. 
EPENTHESIS CYMBALOIDEA, Haeckel. 
This is another mysterious medusa which has been handed down 
to us by the ancient naturalists. Slabber first described it under the 
name of Medusa cymbaloidea in 1775, and Shaw (1789) has copied 
Slabber’s figures and also changed the name to Medusa campanella. 
To judge from the figures given, the medusa appears to be very 
much like Thawmantias hemispherica (Gronovius) with fewer 
tentacles. The generative organs occupy the outer half of the 
radial canals. The medusa was caught by Slabber in the act of 
swallowing a fish, tail foremost, of which a figure is given. 
Lamarck (1817) has copied Slabber’s description, and Eschscholtz 
(1829) changed the generic name to Thaumantias. 
Blainville (1834) has given again Slabber’s account of the species 
and copied his figures, but has left out the wonderful fish. 
Haeckel (1879) has placed all these references under the name 
of Epenthesis cymbaloidea, a genus of the Eucopide,and characterized 
by the possession of 16 marginal vesicles and 16 tentacles. 
Amongst the synonyms Haeckel has placed Thawmantias 
thompsoni, Forbes, which is also given as a doubtful synonym of 
Thaumantias forbesii, Haeckel (Thaumantide, Haeckel). The 
figure of Slabber’s medusa bears no resemblance to Forbes’s species, 
which is more like Phialidium buskianum (Gosse). It only requires 
the addition of the necessary marginal vesicles to make the identi- 
fication complete. These Haeckel has added. 
Eucope gemmigera, Keferstein (1862), is also given as a synonym 
by Haeckel of Epenthesis cymbaloidea. According to Keferstein 
this medusa has a ciliated medusa-bud upon the stomach. I 
prefer for the present to regard this medusa as a distinct species. 
The medusa-bud is not described in detail and the figure shows 
the external shape only. It may bea young stage of the parasitic 
Halecampa, which often attaches itself to the stomach or the 
generative organs of meduse. 
Epenthesis cymbaloidea, Haeckel, and its synonyms have no 
connection whatever with Phialidiwm cymbaloidewm (Van Beneden). 
PHIALIDIUM VARIABILE, Haeckel. 
Under this name Haeckel has united several species which I 
consider to be quite distinct. He gives no less than 26 references 
which are divided into two sets, one for the Mediterranean and 
the other for the Atlantic Ocean. 
Just as in the case of Thawmantias hem*spherica, the early 
writers omitted the marginal vesicles, which amongst the Eucovide 
