ACALEPH.E. 199 



membranous hoods, or lobed coverings, circulating vessels much 

 ramified, and united with a net-work. Of the Gymnophthalmata we 

 have an example in Mquerea violacea (Fig. 84), in which the disk is 

 slightly convex, glass-like in appearance, and furnished all round with, 

 very short, slender, thread-like, violet-coloured tentacula ; with circulat- 

 ing vessels, eight in number, quite simple, and ovaries placed on them ; 

 peduncle wide, expanding into many broad and long fringed lobes. 



Fig. 85. Aurelia uurita (^Lainarck). Cyanea aurita (Cuvier). Oue-third natural size. 



The Steganophthalmata include the Medusadas proper, in which the 

 umbel is hemispherical, with numerous marginal tentacles, eight eyes 

 covered by lobes, four ovaries, four chambers, four fringed arms, with 

 a central and four lateral openings. Aurelia aurita (Fig. 85) is here 

 represented as a type of the group ; it is plentiful in the Baltic, and 

 has been carefully studied by the Swedish naturalists. Eosenthal has 

 made its anatomy his special study. Sars has also made it the subject 

 of observations. In the same group we find the Pelagia cyanella 



