54 SLABBERIA HALTERATA. 



The bulbs at their bases are more or less triangular, coloured above with bright verdigris 

 green, and across the centre with a band of deep orange, below which, on the root as it were 

 of the tentacle, is seen a conspicuous and ©ather large jet-black ocellus. The extremity of 

 each tentacle is likewise swollen into a bulb, which is of a rich orange hue. From the centre 

 of the sub-umbrella hangs a long and highly extensile peduncle or stomach, capable of being 

 contracted entirely within the general cavity, but more usually elongated beyond the length of 

 the tentacula. It is of a denser tissue than the other parts, and terminates in a circular 

 orifice. The termination is not unfrequently swollen into the shape of a bell. The summit 

 projects slightly above the surface of the sub-umbrella. The diameter of the disk does not 

 exceed one eighth of an inch. 



This curious Medusa was observed in August, 1836, in Mount's Bay, Cornwall, where 

 great numbers of them were taken. It swims with its four tentacles either stretched out 

 straight, or at a slight angle, and as if quite stiff, so that they seem with their loaded extremities 

 to serve as poisers. The brilliant terminal bulbs, following at equal distances the conspicuous 

 ocellated bulbs of their bases, give the creature a very striking aspect, and at first glance 

 seem as if they belonged to two Medusae, one of which had partially enveloped the other. 

 The Slahberia halterata is a very active, and apparently hardy little animal. This remarkable 

 combination of characters, and the features quite peculiar to itself, render it well worthy of 

 generic distinction. The position and form of its ovaries indicate a relationship with Thau- 

 mantias, whilst the peduncle is that of a Sarsia. It thus links together genera, which, were 

 it not for such a connecting form, would seem to be far apart. I have dedicated the genus to 

 Martin Slabber, an ingenious Dutchman, who amused himself with the microscope, and 

 published an account of his observations at Haarlem, in 1778. He was one of the first to 

 direct attention to the minuter forms of Medusae inhabiting the German Ocean, and therefore 

 has good claim to preside over a sound generic group. 



Plate VI, f. I, a, represents Slabber ia halterata of the natural size \ \, h, magnified; 

 1, c, disposition of vessels and ovaries, as seen from above; 1, d, ovary; 1, e, a tentacle 

 with its bulbs ; \,f, proboscis when most dilated. 



