832 ME. E. T. BROWIfE ON BRITISH MEDUSji). [NoV. 16, 



vesicle shows considerable variation ; they are usually placed in 

 nearly a straight line, but often form a semicircle, and are occa- 

 sionally arranged in opposite pairs, as described by Haeckel in 

 Polycanna f angina. 



Literature. — A search into the literature relating to the genera 

 JEquorea and Polycanna led me to a paper published by Forbes in 

 the 'Proceedings' of this Society for 1851, "On a Species of 

 ^quorea inhabiting the British Seas," taken in the Outer Hebrides. 

 The medusae taken at Valencia closely correspond to the description 

 and figures given by Forbes, who, after a careful investigation of 

 the early literature, decided that his specimens belonged to the 

 species known as JSquorca forshalea (Peron). I have examined 

 the earlier references relating to this kind of medusa, and believe 

 that it is not possible to recognize with certainty the species 

 described by the early naturalists. 



Haeckel (1879) brings together all the early references relating 

 to J^quorea forslmlea (Peron), but has omitted Forbes's ^quorea. 



Glaus (1881) describes specimens of ^quorea forskalea taken at 

 Trieste, and criticizes Haeckel's classification of the ^quoreidse. 



Hartlaub (1894) describes specimens from Heligoland under the 

 name of ^quorea forshalea (Peron). 



Our present knowledge of this interesting group is certainly not 

 in a very satisfactory condition. Probably, when more is known 

 about them, there will be a considerable reduction in the number 

 of species and Claus's views confirmed. 



For the present I think it is best to leave the Valencia speci- 

 mens under the name of Polycanna forslcalea (Forbes). 



A Leptomedusa (gen. ? sp. ?). (Plate XLIX. figs. 3, 3 «.) 



This is an interesting little medusa which I have found only in 

 Valencia Harbour : a single specimen in May 1895, and three in 

 August 1896. 



Descri])tion. — Umbrella egg-shaped, about 1 mm. in length and 

 ■width. Stomach and mouth absent. Four radial canals. Four 

 brownish tentacle-bulbs, without tentacles. Eight marginal 

 vesicles, each with a single otolilh. About halfway down each 

 radial canal there are three pairs of dark brownish, irregular lobes, 

 which project into the umbrella-cavity. Velum very broad. 



The absence of the stomach and mouth and of" the tentacles, 

 and the presence of lobes on the radial canals, were noticed in all 

 the specimens. 



Gonads probably develop upon the lobes of the canals, but none 

 were visible in these specimens. 



I do not believe that this medusa has been described, and refrain 

 from giving it a name. Most likely it comes from a Calyptoblastic 

 hydroid which has probably already received a name ; if so, let it 

 receive its hydroid name \ 



^ Since this paper was read Dr. 0. Hartlaub has published a description of this 

 medusa from examples taken off Heligoland. It is named Acjastra mira (sp. et 

 gen. nov.). (Arbeiten bid. Aiistalt Helgoland, 1897, Bd. ii, p. 504.) 



