TUBULARIA SOLITARIA. 83 



On Tubularia solitaria sp. nov., a Hydroid 

 from the Natal Coast. 



By 



Ernest Warreii, D.Sc.L.oiid., 



Director of the Natal Government Museum. 



With Plates X and XI. 



This hydroid has been collected at several places along- 

 the Xatal Coast. It is solitary in habit, and I haye only 

 found it attached to sponges. The species of sponge is not a 

 matter of indifference; for, although a certain siliceous scarlet 

 sponge is exceedingly common on this coast, yet I have never 

 found the hydroid attached to it. I have only discovered it 

 on a certain siliceous dark maroon coloured sponge and on a 

 siliceous white sponge. The hydroid occurs between the tide 

 marks, and is imbedded in sponges covering the surfaces of 

 rocks which happen to be somewhat protected from the 

 violence of the waves. The individual hydroids may generally 

 be seen in clumps irregularly scattered, and spreading over 

 a considerable area of sponge. 



Trophosome. — The hydroid varies in height, but its 

 maximum length projecting beyond the general surface of 

 the sponge is about half an inch (PI. X, figs. 1 and 2). It 

 may be seen by the naked eye that the endoderm of the 

 hydranth and of the gonophores is of a beautiful rose-red 

 colour, while the tentacles and the hydrocaulus are tran.s- 

 lucent and whitish. The hydroid is fixed to a considerable 



