CCELENTEEATA : HTDROZOA. 81 



The reproductive bodies in the CalycopJwridce are in the 

 form of medusiform gonophores, which are budded from the 

 peduncles of the polypites, becoming, in many instances, 

 detached to lead an independent existence. In some Calyco- 

 phoridcB, as in Abyla, ' each segment of the ccenosarc, provided 

 with a polypite, its tentacle, reproductive organ, and hydro- 

 phyllium, as it acquires a certain size, becomes detached, and 

 leads an independent life the calyx of its reproductive organ 

 serving it as a propulsive apparatus. In this condition it may 

 acquire two or three times the dimensions it had when 

 detached, and some of its parts may become wonderfully 

 altered in form.' (Huxley.) To these detached reproductive 

 portions of adult Oalycophoridce the term ' Diphyozooids ' has 

 been applied. 



As regards the development of the Calycophoridce, 'not 

 only the new polypites, but the new nectocalyces and repro- 

 ductive organs, and even the branches of the tentacles, are 

 developed on the proximal side of the old ones ; so that the 

 distal appendages are the oldest.' (Huxley.) The process 

 of development is, therefore, the reverse of what obtains 

 amongst the Hydroida. 



Diphyes, which may be taken as the type of the Calyco- 

 phoridce, consists of a delicate filiform ccenosarc, provided 

 proximally with two large mitre- shaped nectocalyces, of which 

 one lies entirely on the distal side of the other. The pointed 

 apex of the distal nectocalyx is received into a special cavity 

 in the proximal nectocalyx. The * hydrcecium' is formed 

 partially by this chamber in the nectocalyx, and partially by 

 an arched groove prolonged upon the inner surface of the 

 distal nectocalyx, within which the ccenosarc moves freely 

 np and down, and can be entirely retracted if necessary. The 

 upper part of the ccenosarc dilates into a small ciliated cavity, 

 from which are given off two tubes, which proceed respectively 

 to the distal and proximal nectocalyces, where they open 

 into the central chamber from which the nectocalycine canals 

 take their rise. The upper portion of this small ciliated 

 cavity is prolonged proximally into the larger chamber of the 

 1 somatocyst.' The ccenosarc bears polypites, each of which is 

 protected by a delicate glassy ' hydrophy Ilium.' 



DIVISIONS OF THE CALYCOPHORIDJE. (AFTER HUXLEY.) 



Fam. I. Dipki/d(S. Nectocalyces not more than two in number, and of 

 a polygonal shape. Hydrcecium of the proximal nectocalyx complete, or 

 closed posteriorly. Hydrophyllia well developed. 



Fam. II. Sphceroncctida. Nectocalyces probably not more than two in 

 number ; the proximal nectocalyx spheroidal, with a complete hydrcecium. 

 No hydrophyllia (?). 



VOL. I. G 



