in d. Naturgesch. d. nied. Thiere währ. d. Jahre 1872—1875. 447 



T. bellis Allm., T. attenuata AUm., T. simplex Alder (= T. Dumor- 

 tieri Johnst.), T. humilis Allm., T. calamaris van Bened,, T. pohj- 

 carpa n. sp. Süd-America, T. spectabilis Ag,, T. tenella Ag., T. pa- 

 cifica n. sp. Still. Oc. 



Subg. Parypha Ag. Sporosacs without evident gastro-vascular 

 canals; apical processus in female sporosacs laterally compressed. 

 T. crocea Ag., T. cristata Mc Cr., T. mesemhryanthemmn n. sp. la 

 Speccia. 



Provisorisch : T. aspera n. sp. Süd-Amer. 



Farn. Hybocodonidae. Hydrocaulus developed, invested by 

 a chitinoous perisarc. Hydranths with a proximal and a distal set of 

 filiform tentacles. Gonophores medusiform planoblasts. 



Hybocodon Ag. Hydrophyten consisting of a simple (or bran- 

 ched?) hydrocanlus, rooted by a filiform hydrorhiza. Hydranths flask- 

 shaped, abruptly distinct from the supporting hydrocaulus; the pro- 

 ximal set of tentacles long and forming a single verticil, the distal 

 set short and arranged on two distinctly separated verticils, Plano- 

 blasts springing from the body of the hydranth, betwcen the pro- 

 ximal and distal set of tentacles. Medusa at the time of liberation 

 with a deep-bell-shaped urabrella, simple-mouthed manubrium, four 

 radiating canals and with only one marginal tentacle, wich is pro- 

 longed from the distal extremity of one of the canals and is fur- 

 nished with a bulbous base destitute of distinct ocellus. 



H. prolifer Ag. 



Ectopleura Ag. Hydrocaulus filiform, rooted. Hydranths flask- 

 shaped abruptly marked of from the supporting stalk; tentacles of 

 the proximal set longer than those of the distal. Planoblasts on 

 branched peduncles, which are borne on the body of the hydranth 

 between the proximal and distal verticils of tentacles. Medusa at 

 time of liberation with a nearly spherical umbrella and simple-moun- 

 thed manubrium; four radiating canals and four marginal tentacles; 

 no distinct ocelli; umbrella furnished with eight prominent longitu- 

 dinal ribs, formed of linear series of thread-cells. 



E. Dumortieri van Bened. 



Fam. Hydrolaridae. Hydrocaulus undeveloped. Hydranths 

 with but two tentacles, wich are filiform and spring from one side 

 of the base of the hypostome; mouth with two lip-like lobes. Gono- 

 phores medusiform planoblasts with six simple radiating canals and 

 simple marginal tentacles. 



Lar Gosse. Hydrorhiza a creeping filiform stolon covered with 

 perisarc; hydranths fusiform; hypostome separated by a constriction 

 from the body; oral lobes in the form of two opposable plates. 

 Planoblasts borne on blastostyles which spring from the hydrorhiza 

 and terminate distally in a globular Cluster of thread-cells. Medusa 



