200 THE OCEAN WORLD. 



of Peron, whose body is globose, scolloped with eight marginal ten- 

 tacles, peduncles ending in four leaf-like, furbelowed arms, united at 

 the base, having four ovaries, and appendages to the stomach, without 

 orifices. 



The Pelagia, as the name implies, belong to the deep sea. P. noe- 

 tiluca has a transparent, glass-like disk, of a reddish-brown colour and 

 warty appearance. It is found in the Mediterranean, about the coast 

 near Nice, and is still more plentiful on the coast of Sicily, and on the 

 African coast. Another species, P. panopyra, is very common in the 

 Atlantic and Pacific, between the Tropics. The naturalist Lesson met 

 whole banks of them in the equatorial ocean, about the twenty- 

 seventh degree north latitude and the twenty-second degree west lon- 

 gitude. During the night, this species emits a brilliant phosphoric 

 light, and living individuals, which Lesson succeeded in preserving, 

 exhibited great luminosity in the dark. This medusa is remarkable for 

 its semi-spherical disk, slightly depressed, umbilicate at the summit, 

 a little compressed at the edges, and densely bristling on the surface 

 with small elongated warts, but regularly festooned along the edges. 

 In colour it is a delicate rose. 



The animals which constitute this class of Zoophytes, and, in former 

 times, so curious and so imperfectly known, were designated Polypo- 

 medusze, in order to remind us that at one time they were called 

 Medusse, and at others ranged among the Polyps. It has,' however, 

 been recently discovered that, shortly after they issue from the egg, 

 these zoophytes show themselves in the form of polyps, and that, at a 

 later period, they assume the animal form, to which we give the name 

 of medusse. These animals are, then, true proteans : hence the very 

 considerable difficulty of studying them difficulties which have long 

 reduced naturalists to despair. Even now their history is too obscure 

 and too complicated to justify us in presenting it, except in its general 

 features. We shall, therefore, content ourselves here with a descrip- 

 tion of the best known species of the class only those, namely, which 

 have particularly attracted the attention of naturalists, and which are, 

 at the same time, of a nature to interest our readers. 



The class of Discophorae may be divided into four orders or families, 

 namely : 



I. THE HYDRAID^E, having single, naked, gelatinous, sub-cylindrical, but very con- 



