1896.] BEITISn HTDmOIDS AND MEDUSAE. 489 



ment. Owing to the ripe state of the ova in some of the specimens, 

 I was able to distinguish the species as Thaumantias huskiana, 

 Gosse. It is quite distinct from Pliialidium temporarinm and 

 Phialidium cymhaloideiim, as the generative organs never extend 

 along the outer half of the radial canals, and are always round 

 or slightly oval in shape. 



It may be difficult to distinguish this species in its early stages 

 from Phialidium temporarium. I have not yet met with the two 

 species together ; the latter appears in the spring and the early 

 part of the summer, and the former in the autumn. 



Gosse named this species after Busk (1849), who described a 

 similar medusa (without giving it a specific name) taken in the 

 Solent during the autumn of 1848. 



Unfortunately Busk's figures of the medusa are useless for 

 identification. 1 believe tliat Busk took specimens of this species 

 and also of other species which he has confused with it. 



Gosse was the first to give this species a description by which 

 it may be readily identified. The following is an abstract of the 

 description : — Umbrella when young globose, when older hemi- 

 spherical or shallow campanulate, from 2 to 6 mm. in diameter, 

 transparent and colourless. The margin of the umbrella fringed 

 with 20-32 tentacles, very slender and extensile, with yellowish 

 basal bulbs. A marginal vesicle between every two tentacles ; some- 

 times two vesicles present, and occasionally a vesicle has two 

 otoliths. Ovaries small, oval, on the radial canals, containing 

 globular ova in various degrees of development. Stomach small 

 and quadrangular. Taken at Ilfracombe in the autumn. 



The Plymouth specimens agree with the description given by 



The species closely resembles Phialidium variabile (Claus), from 

 the Mediterranean. I prefer to keep them separate for the 

 present until the hydroid forms have been identified. 



Italso closely resembles the figure given by Forbes of Thaumantias 

 thompsoni, which was taken by Forbes on the coast of Cornwall 

 and in Boundstone Bay on the west coast of Ireland. 



Bohm (1878) has described the medusa under the name of Clytia 

 johnstoni from Heligoland. 



Hartlaub (1894) has recorded Phialidium variabile (Claus) (not 

 Haeekel) from Heligoland. 



Phialidium tempoeabium, Browne. (Plate XVII. figs. 4, 5, 6.) 

 I find it is necessary to give a specific name to one of the 

 commonest medusa) on our coasts. It is probable that Forbes 

 described this species under the name of Thaumantias hemisphcerica, 

 but as Haeekel has taken Thaumantias hemisphmriua as the type of 

 the genus Thaumantias, and many other naturalists have placed 

 the species upon their lists, it is necessary to retain it. I have 

 already described some specimens of this species under the name 

 of Phialidium variabile, Haeekel, in the ' lleport on the Isle of 

 Man Medusae'; but I have since discovered that Phialidium 



