PRAYA. 53 



nectocalyx, with the other floating horizontally, and allowing the coenosarc to depend perpen- 

 dicularly from its under surface. 



In order to enable those into whose hands this work may fall to comprehend the 

 relations of this detached organism to Prai/rt, I add the following short account of that genus, 

 founded upon the statements of the authors just mentioned. 



The nectocalyces are two, placed at the upper extremity of a coenosarc, which some- 

 times (in P. maxima on Gegenbaur's authority), attains a length of three feet, and are nearly on 

 the same level. One is usually smaller than, and more or less embraced by the edges of, the 

 other. They are both of a gelatinous consistence, reniform, and more or less bilobed below. 

 A shallow nectosac occupies the lower and outer end of each. Both nectocalyces are attached 

 by a muscular expansion to the proximal end of the coenosarc ; and the somatocyst is a long, 

 curved canal, which sends a blind process downwards between the nectosac and the 

 hydroecium. The latter is a widely open groove, or shallow pit, in both nectocalyces, 

 and the chamber into which the coenosarc is retracted is formed by the application of the 

 edges of these grooves to one another. 



In the natural position, therefore, the long axis of this composite hydroecium is vertical, 

 and, consequently, the long axes of the nectocalyces are also vertical ; and the mouths 

 of their nectosacs are directed outwards and downwards. 



Each hydrophyllium is a thick, gelatinous, and reniform body, bent upon itself, rounded 

 and solid at one extremity, and divided at the other into a median thick and two lateral 

 lamellar lobes. The phyllocyst is prolonged into four csecal processes. 



The calyx of the reproductive organ is provided with two strong, longitudinal crests, 

 and the same hydrosoma presents gonophores of both sexes. 



Two species of doubtful distinctness^ {P. diphyes and P. maxima) are described. They 

 have been taken in the Mediterranean and in the tropical parts of the Atlantic and Pacific 

 Oceans. 



^ See Leuckart, Z. N. K., p. 40. 



