TIYDROZOA. 99 



'Nectocalyces horse-shoe shaped . . . Hqrjopodius. 

 Nectocalyces concave externally, " and pro- 

 4. < duced into five points of which the three 

 xipper are much longer and stronger than 

 the two lower." ..... Vogtla. 



Pray a, Hippopodius, and Vogtla have 'in- 

 complete' hydroecia, the nectocalycine groove along 

 which the coenosarc glides not forming, in these 

 genera, a closed canal. In Praya, however, the 

 two, nearly sjrmmetrical, terminal nectocalyces have 

 their open grooves so applied to each other as to 

 form, by their apposition, a short tube (^fiff. 4, cl). 



The polypites and tentacles of the several genera 

 of Ccdycophoridce present no very striking differ- 

 ences of structure. 



Not so, however, the hydrophyllia. Abyla, the 

 genus most closely allied to Diphyes, is distin- 

 guished from that form not merely by its necto- 

 calyces, but also in having thick, facetted, hydro- 

 phyllia, the edges of which do not overlap one 

 another. In Diphyes the hydrophyllia are folia- 

 ceous, smooth externally, slightly convex, ?md folded 

 so that their edges freely overlap. 



In Praya, " 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 caecal processes." But in Vogtia, Hippopo- 

 cZii^s, and, perhaps . also, Sphceronectes, these or- 

 gans are absent altogether {fig. 20, b). 



The reproductive bodies of the Calycophoridce 

 are always medusiform, and attached to the pe- 

 duncles of their respective polypites. In Vogtia 

 and Hippopodius the manubrium attains a large 



H 2 



