440 Leuckart: Bericht üb. d. wissenschaftliclien Leistungen 



Cionistes Wrght. Hydrophyten consisting of a retiform hydro- 

 rhiza without developed hydrocaiüus. Hydranths sessile on the hy- 

 drorhiza, minnte, with a single verticil of filiform tentacles. Sporo- 

 sacs borne by blastostyles, which spring from the hydrorhiza. 



C. reticulata Wrght. 



Farn. Bougainvillidae. Hydrocaulus more or less developed, 

 invested by a conspicuous perisarc. Hydranths with the hypostome 

 not abruptly difFerentiated; tentacles filiform, in a circlet round the 

 base of the hypostome. Gonophores phanerocodonic, with four simple 

 radiating canals, and with the marginal tentacles simple and distri- 

 buted either singly or in Clusters. 



Bougainvillia Less. Hydrophyten consisting of a branching 

 hydrocaulus, which is rooted by a filiform hydrorhiza. Hydranths 

 fusiform, with a conical hypostome. Planoblastes (= Hippocrene 

 Brdt., Margeiis Steenstr.) borne by the hydrocaulus and having at 

 the time of liberation a deep bell-shaped umbrella, with the manu- 

 brium shorter then the height of the bell-cavity and with four simple 

 labial tentacles, each of which carries at its extremity a little capi- 

 tulum of thread-cells; radiating canals, each terminating at itsjun- 

 ction with the circular canal in a bulb, from which two tentacles 

 are developed, each tentacle having an ocellus at its base. 



B. ramosa van Bened., B. fruticosa Allm., B. superciliaris Ag., 

 ß. carolinensis McCr., B. rauscus Allm. Unsicher: B. Mertensii A. 

 Ag. und Eudendrium pusillum Sars. 



Diplura n. gen. Hydrophyten solitary, rooted by a filiform 

 hydrorhiza, and surmounted by a claviform hydranth. Planoblasts 

 springing from the body of the hydranth at the proximal side of ten- 

 tacles. Umbrella deep bell-shaped; manubrium with simple or qua- 

 drilobate mouth; radiating canals terminating each in a marginal 

 bulb, one of which, in the mature medusa, carries a pair of filiform 

 tentacles, the others being destitute of tentacles. 



D. fritillaria Steenstr. 



Perigonimus Sars. Hydrophyten consisting of a branching or 

 simple hydrocaulus rooted by a filiform hydrorhiza. Hydranths fusi- 

 form, with a conical hypostome. Planoblasts developed from the 

 hydrophyton. Umbrella at the time of liberation, deep bell»shaped, 

 with the oral extremity of the manubrium either simple or more 

 or less deeply lobed; marginal tentacles either two or four, not in 

 Clusters, and with bulbous bases, which are not furnished with di- 

 stinct ocelli. 



P. muscoides Sars, P, repens Wrght (= Eud. pusillnm Wrght), 

 P. minutus Allm., P. sessilis Wrght, P. palliatus Wrght., P. vestitus 

 Allm., P. serpens Allm., P. linearis Alder. Zweifelhaft: AtractyUs 

 bitentaculata und A. quadritentaculata Wrght. 



