EEPOET ON THE SIPHONOPHOR^E. 



177 



composed of innumerable small paliform cnidocysts ; on each side of it lies a bunch of a 

 few large ensiform cnidocysts (usually four to eight, rarely more). 



Gonophores. — The sexual medusomes of all Polyphyidae come to maturity whilst 

 sessile on the stem. There is, therefore, in this family no true metagenesis, as in the 

 Diphyidse and Monophyidte. The cormidia are sometimes diclinic {Hippop>odius), at 

 other times monoclinic (Polyphyes and Vogtia). Usually the gonodendra are small, and 

 only one or two large mature gonophores exist between a small number of immature 

 and young buds. Usually in the diclinic corms the female gonophores occupy the 

 superior, the male gonophores the inferior part of the siphosome. The gonophores of 

 both sexes have a well-developed, hemispherical or campanulate umbrella, with four 

 radial canals and a connecting ring-canal above the small velum. The manubrium, from 

 the exoderm of which the sexual cells are developed, is ovate, spindle-shaped or cylin- 

 drical ; it becomes very large and widely protruded through the ostium of the 

 subumbrella, often two to four times as long as the latter, or even more. Thus the 

 form of the gonophores in the Polyphyidae is more like that in the Physoneetae than 

 in the other Calyconectse. 



Synopsis of the Genera of Polypliyidie. 



I. Subfamily Hippopodioe. ] Ostium without teeth, cormidia diclinic, . 

 Nectophores rounded, not > 



prismatic. ) Ostium with six teeth, cormidia monoclinic, 



II. Subfamily Vogtid.e. 



Nectophores five-sided, pris- J- Ostium with five teeth, cormidia monoclinic, 

 niatic. 



33. Hippopodius. 



34. Polyphyes. 



35. Vogtia. 



Subfamily Hippopodid^e. 



Genus 33. Hippopodius, 1 Quoy and Gaimard, 1827. 

 Hippopodius, Quoy and Gaimard, Ann. d. Sci. Nat. (ZooL), t. x. 



Definition. — Polyphyidae with rounded horseshoe-shaped nectophores, the ostium of 

 which is smooth or sbghtly lobate. (Cormidia diclinic. Gonophores attached to the 

 base of the siphons. ) 



The genus Hippopodius is the most common of the three genera of Polyphyidae, and 

 is represented by the well-known Mediterranean type Hippopodius gleba, and by several 

 similar species, which are widely distributed over all warmer seas. I found single 

 detached nectophores of it in different bottles in the Challenger collection, taken in the 

 Tropical Pacific and Atlantic ; and also in the collection of Captain Rabbe, from the Indian 



1 Hippoj)odius = Horse-shoe, iVxof, woS/o 



(ZOOL. CHALL. EXP. — PART LXXVII. — 1888.) 



Hhhh 23 



