^00 PERCY SLADEN TRUST EXPEDITION 



in the form of a solid chord of cells. The gonads are developing on the outer third of the 

 lower wall of the stomach in a continuous ring, which is without any projecting pouches. 

 There are eight tentacles, about as long as the diameter of the umbrella ; they are not 

 very stiff, and taper to a fine point. Below each tentacle is a well-marked peronial 

 groove, lined with nematocysts. On each of the eight marginal lappets are five sense 

 organs, rather ovate in shape, showing a clear circular vesicle, and without any extei'nal 

 hairs. Otoporpae are present as narrow bands just curling over the margin of the 

 umbrella and situated on ridges. 



The other specimens are smaller in size and very much contracted. Two of them 

 have nine tentacles. 



It is difficult to assign a specific name to these specimens, as some are certainly quite 

 young stages and the largest has not reached maturity. They come nearest to Haeckel's 

 Solmaris lenticula from the Indian Ocean. ■ This species was only briefly described and 

 never figured by Haeckel. Mayer thinks that it was probably only an immature form. 



39. ^GiNA CITREA, Eschscholtz, 1829. 



^gina citrea, Maas, 1905, p. 71, Taf. 11, fig. 72, Taf. 13, figs. 79—82. 

 jEgina citrea, Bigelow, 1909, p. 73, pi. 1, fig. 5, pi. 14, fig. 5. 



Locality. Chagos Archipelago, Peros Atoll. 600 — fms. 30 June, 1905, N. 

 1 specimen. 



I am not certain about the correct determination of this specimen, which is far from 

 being perfect. The umbrella has a rather rounded summit, and measures 1 4 mm. in width 

 and 7 mm. in height. There are eight stomach-pouches, one of which shows signs of 

 a small notch in the middle of the lower edge ; the other pouches are either without 

 a notch or in an imperfect condition. Four tentacles about 30 mm. long. The margin of 

 the umbrella is imperfect, but four sense organs were seen in one octant. 



Genus SoLMUNDELLA, Haeckel, 1879, ex Maas, 1904. 



This genus is found in all the oceans from the tropics to the icy waters of the poles. 

 It is quite easy to determine the genus even from very bad specimens, but one has yet to 

 settle the exact number of species, and this delicate point is not so easily disposed of. 



Vanhoffen considers that the genus has only a single species, which he calls 

 Solmundella hitentaculata, after the oldest specific name. The doubtful species is 

 known as Solmundella mediterranea. Whether this is a good species, or a variety of 

 Solmundella hitentaculata or identical with it, is a point which, in my opinion, requires 

 further researches. 



Maas and Bigelow evidently recognise two species ; Mayer is very doubtful, and only 

 ranks Solmundella m,editerranea as a variety. As in the case of Liriope, I think that 

 there are at least local races of Solmundella. The difficulty is to make sure of their 

 status. Are they distinct species or varieties 1 If it should be finally decided that there 

 is only one species, then I think that local races should be recognised by names for the 

 sake of geographical distribution. 



