ON PARAWRIGHTIA EOBUSTA. 187 



On Parawrightia robusta gen. et sp. nov., a 

 Hydroid from the Natal Coast ; and also an 

 Account of a Supposed Schizophyte occur- 

 ring in the Gonophores. 



By 



Ernest \l^arreii, D.Sc.L.oii<l. 



Director of the Natal Government Museum. 



With Plates XXXIII and XXXIV. 



This hydroid has been found at several places on the Natal 

 coast. It was first collected at Park Rynie, and subsequently 

 at Isipingo and Scottsburg. These places are situated thirty 

 to forty miles south of Durban. The hydroid is not very 

 common ; it occurs attached to sea-weeds and sponges in the 

 rock-pools near the low-water line. 



(1) Trophosome. — It consists of a creeping stolon, about 

 025 mm. in diameter, forming an irregular reticulum on 

 the surface of the foreign body to which it is attached 

 (PI. XXXIII, figs. 1, 2). From the reticulum there spring 

 upright stems 5 — 12 mm. in height, which usually bear a 

 single terminal polyp. Occasionally the stem may produce 

 one or even two short lateral branches, each carrying a 

 hydranth. 



The growth of the stolon or reticulum is not by any means 

 limited to apical growth. Almost any part of the stolon 

 appears to have the power of sending out bud-like swellings. 

 The ectoderm under the thick perisarc proliferates, forces its 

 way through the perisarc, and is at first only covered by the 



