106 



LOWER INVERTEBRATES. 



;^ 



knobs, or pendant side-brandies. At the point of attachment of the polypite to the 

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



with eggs and spermatozoa. 



Each cluster of bodies near 



a polypite ultimately sepa- ffvS-Wi 



rates from its attachment to 



the Dlphyes axis, lives in- 



dejjendently, and is called 



a diphyizooid. 



There are several families 



related to the Diphyidas 



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 genus composing a 



family called the Peayidjj. , // 



In Praya there are two 



nectocalices which are of 



about equal size, and have a 



rounded or semi-ovate form. 



The bell M-alls are not as 



rigid as those of Piphyes, 



and their 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-shaped 



covering - scale, beneath \ " X^X]^ 



which are found clusters of 



sexual bells mounted on 



short peduncles. The 



genus is one of the most '^^V-^-. ^ 



striking of the many beau- 

 tiful genera which charac- 

 terize the Siphonophore 



fauna of the Mediterranean 



Sea. I have also observed 



a fragment of a large Praya 

 near Fort Jefferson, Tortugas, Florida. 



The fourth of the large gi-oups into which the true Siphonophora may be divided 

 is called the Hippopodi^ from a genus sometimes called Hippopodms., which has a 

 highly characteristic and peculiar structure. G-leba {Hippopodius) is in most respects 

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

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



FiG. 99. — Biphyes. 



Fig. 100. - 



