280 PllOr. ALLMAN ON NEW GENERA 



forwards for a short distance from its posterior wall ; mesial 

 nematophore adnate for the greater part of the height of the 

 hydrotheca, and then becoming free for a short distance ; lateral 

 nematophores long, cylindrical, diverging ; each internode of the 

 primary pinnae carrying two cauline nematophores close to the 

 base of the secondary pinna. 



Gonosome. Gronangia compressed, cup-shaped, opening by a 

 wide orifice at the distal end, springing by a very short latero- 

 basal peduncle from the back of each secondary pinna close to 

 its origin. 



Locality. Ceylon, Mr. Holdsioorth. 



The doubly pinnate ramification of S. hipinnata impresses on 

 the Hydroid a striking physiognomy. The species is rendered 

 still further remarkable by the large size of its strong rigid 

 hydrocaulus, while the branches, being given off to the right and 

 left, lie mostly in the same plane, and confer on it somewhat the 

 aspect of certain species of Antipathes or Gorgonia. The hydro- 

 thecae are proportionally small ; and the pinnae which carry them 

 are slender and easily detached from the rest of the hydrocaulus. 

 Though the hydrothecas resemble those of the macrorynchial 

 species in the forward direction of the orifice and in the deep 

 involution of the anterior wall, the free portion of the mesial 

 nematophore is but little developed, and is provided with only 

 the terminal aperture. 



The main stem and branches are strongly fascicled ; and the 

 principal tube of the primary non-hydrotheca-bearing pinnae (that 

 from which the secondary pinnae arise) is accompanied by two or 

 three tubes from the branches, which, however, soon cease ; and 

 the primary pinna then continues its course as a single tube. 



Some of the specimens were loaded with gonangia, which were 

 always very thin-walled and provided with a very wide orifice ; 

 but how far the form of these receptacles in the dried specimens 

 corresponded with their condition in the living animal is somewhat 

 doubtful. Their origin from the back of the hydrocaulus is very 

 remarkable, and quite exceptional in the group. 



