274 PROF. ALLMAN ON IS'EW GENERA 



coutractiug below into a short curved peduncle, marked by shal- 

 low transverse corrugations towards the summit, and terminated 

 by a slightly elevated aperture. 



Locality. Japan, Gapt. St. John. 



This Hydroid has much the habit of certain true Thuiarios. It 

 is a large and beautiful species. The specimens were loaded with 

 gonangia, which were confined to the basal portion of each system 

 of bifurcating ramuli, where the hydrothecse are separated from 

 one another by intervening spaces ; it is from these spaces that 

 the gonangia arise in two longitudinal rows upon the upperside 

 of the ramulus. The gonangia-bearing portion of the ramulus is 

 separated from the more distal portion by a transverse joint. 



FLUIIULABIIDjE. 

 Aglaophenia. 

 Aglaophenia acanthocarpa. Plate XXI. figs. 1-4. 



Trophosome. Hydrocaulus attaining a height of upwards of 

 three inches, irregularly branched, pinnse springing from the 

 anterior aspect of the stem. Hydrothecse closely approxi- 

 mate, rather deep, gradually expanding upwards, margin deeply 

 toothed, with the second tooth from the front on each side 

 strongly everted; intrathecal ridge strong, extending from about 

 the middle of the back of the hydrotheca transversely to within 

 a short distance of the anterior mesial line ; mesial nematophore 

 adnate to the front of the hydrotheca from its base to its margin, 

 and then becoming free, and extending forwards and upwards as 

 a long thickish beak -like process, in which there is a lateral as 

 well as a terminal orifice ; lateral nematophores overtopping the 

 hydrotheca, very divergent in a front view ; rachis of pinna with 

 an imperfect septum continuous with the intrathecal ridge, and 

 another oblique one at the base of the lateral nematophores. 



Gonosome. Corbulse open, with a short stalk, and with about 

 eighteen pairs of free leaflets, which decrease in length towards 

 the distal extremity of the corbula, and give ofi" on each side 

 numerous closely set, long, opposite, blunt spine-like nemato- 

 phores ; each leaflet with a double nematophore near its base. 



Locality. New Zealand, Mr. Susie's collection. 



This is a very elegant species, with much of the habit of our 

 European Ar/laopJienia pluma. Its hydrothecse are remarkable 

 for the great development of the free portion of the mesial nema- 



