106 



LOWER INVERTEBRATES. 



■n' 



knobs, or pendant side-branches. At the j)oint of attachment of tlie iiolypite to the 

 axis, we also iind a transparent bell-shaped covering-scale and a cluster of sexual bells 

 with eggs and spermatozoa. 

 Each cluster of bodies near 

 a jiolypitc ultimately sepa- 

 rates from its attachment to 

 the Diphijes axis, lives in- 

 dependently, and is called ^f" 

 a diphyizooid. 



There are several families 

 related to the Diphyidfe 

 which might be mentioned. 

 They differ from it in the 

 character, size, and general 

 anatomy of the two necto- 

 calices. One of the most 

 marked of these is Praya, 

 a solitary genns composing a 

 family called the Peayid.e. 

 In Praya there are two 

 ncctocalices 'which are of 

 about equal size, and have a 

 rounded or semi-ovate form. 

 The bell walls are not as 

 rigid as those of Diphyes., 

 and (heir motion less spas- 

 modic. The axis is very 

 long and flexible, and the 

 polypites, found at intervals 

 along its length, are pro- 

 tected by a helmet-shajK'd 



covering - scale, beneath ^ ^X~V^ 



which are found clusters of 

 sexual bells mounted on 

 short peduncles. The 



genus is one of the most ^^^\-,^ '^' 



striking of the many beau- 

 tiful genera which charac- 

 terize the Sijihonophore 

 fauna of the Mediterranean 

 Sea. I have also observed 

 a fragment of a large Praya 

 near Fort Jefferson, Tprtugas, Florida. 



The fourth of the large groups into which the true Sijihonophora may be divided 

 is called the Hippopodije from a genus sometimes called Hippopodms, which has a 

 highly characteristic and peculiar structure. Gleba (Jlippopodius) is in most respects 

 related to the Diphyse, but unlike them has more than two ncctocalices. There is no 

 float and no extended axis with individuals found at intervals in its length. No polyp- 



FlG. 00. — Diplii/e, 



Fig. 100. — Praija. 



