THAUMANTIAS MELANOPS. 45 



Many specimens of all ages, all preserving the peculiar characters mentioned, occurred 

 at Tarbet, in Loch Fyne,in company with Thaumantias quadrata, during the autumn of 1845. 

 We had previously taken it by the tow-net at Oban. 



Plate VIII, fig. 4, «and S, represent this species magnified, seen in profile and from above; 

 4, c, is an ovary ; 4, d, the stomach ; 4, e, part of the margin and tentacula ; 4,/, the bulb 

 of one of the tentacles. 



*** Marginal tentacles sixteen and upwards, 

 t Umbrella very convex or globose. 



5. Thaumantias maculata, Forbes. 



Plate IX, Fig. 4. 



The umbrella of this very distinct species is globular, smooth, pellucid, and colourless. 

 The margin of its rather contracted opening is ornamented with sixteen jet-black ocelli, 

 (3 X 4+4), which are alternately larger and smaller, and all very conspicuous, and large in 

 proportion to the body. Between each of these is a small colourless tubercle. From each of 

 the ocelli springs a colourless tentacle. All the marginal tentacles are similar, and very 

 nearly of a size. The sub-umbrella is hemispherical, and divided into four equal segments 

 by the gastric vessels. On its lower half, in the course of the vessels, are four ovate repro- 

 ductive glands, pale, with yellow or tawny centres. From the centre of the sub-umbrella 

 hangs a short but wide campanulate stomach, with four broad, slightly fimbriated lips. 

 The four lips correspond in position to the four ovaries, and on the sides near the base of 

 the stomach, alternating with the lips, are four patches of black pigment-cells, giving the 

 centre of the animal, when seen from above, the appearance Of being marked by four 

 conspicuous black spots. The black bulbs of the tentacles, when compressed and highly 

 magnified, are seen to be coloured by a crescentic series of black pigment-cells, forming the 

 ocellus, bounding a tawny space in which there is seen an otolitic capsule. The tentacula 

 themselves have a highly annulated appearance. The body measures about a quarter of an 

 inch in height. I have met with this curious Thaumantias in the Zetland Islands only. It 

 occurred several times in the Sound of Brassay, but was never plentiful. The jet-black eyes 

 and stomachal spots render it a very striking object in the water. 



Plate IX, f. 4, a, represents it rather more than twice the natural size ; 4, b, as seen from 

 above ; 4, c, the ocellated bulbs ; 4, d, the base and portion of a tentacle highly magnified, 

 showing the distinction between the ocellus and otolitic capsule in the bulb ; 4, e, the stomachy 

 with its lips, spots, and the origins of the gastric vessels, seen from above ; 4, /, one of the 

 reproductive glands. 



6. Thaumantias melanops^ Forbes. 



Plate X, Fig. 3. 



Another black-eyed beauty, though unarmed with such jetty piercing orbs as the sister 

 species last described. Instead of a few conspicuous ocelli, we have here an almost countless 

 number, all, however, of extreme minuteness. Argus, the hundred-eyed, must yield to our 

 Thaumantias, for it has twice as many. 



The umbrella of the Thaumantias melanops is sub-orbicular, inflated, very tender. 



