A COLLECTION OF HYDROIDS. 275 



structure descril)ed in E. parv^um is, doubtless, strictly homo- 

 l()o-ous with the sheath of vaginatum, only in the former 

 species it does not envelop the body to such an extent. 



The nematocysts of the tentacles are somewhat small, and 

 liave a length of 4*8 f.i, and breadth 2-1 ^, 



The endoderm at the base of the hypostome consists of 

 elongated cells with large granules (PL XLV, fig. 2, (jl. c). 

 I'he endoderm of the vertical sides of the polyp is very thin, 

 jmd it contains some flattened granular cells. Towards the 

 base of the polyp the endoderm cells are conspicuously 

 vacuolated {v. c). 



Systematic Position. — From the ])ublished descriptions of 

 \\. capillare Alder, it is not possible to identify the Natal 

 livdroid with this species. The characters in which it differs 

 are : the three-chambered condition of the male gonophore, 

 the absence of a well-defined terminal tubercle to the gono- 

 ])hore, and the extension of the perisarc over the base of the 

 ]>olyp. In the last character, an approach is made to the con- 

 dition seen in E. vaginatum. In Eudendrium insigne 

 Hiiicks a shallow circular groove near the base of the hydranth 

 is mentioned and figured by Allman, and doubtless it has the 

 same structure as that described in E. parvum. 



(3) E u d e n d r i u m a n g u s t n m sp. u . (PI. XLV, figs, o, 6.) 



This hydroid was dredged from a depth of 40 fathoms in 

 the neighbourhood of Bird Island, off Algoa Bay. The speci- 

 men was torn from its attachment, and the hydrorhiza is 

 unknoAvn. It was about 3 inches in height, and of a dark 

 brown colour. 



Trophosome. — H y d r o c a u 1 u s , — Monosiphonic, aborescent, 

 irregularly branching; the stems which immediately carry 

 the branches bearing the hydranths have occasional groups of 

 annulations, and the branches are annulated at their origins, 

 iind have irregularly scattered groups of 2-10 rings. The 

 ])erisarc is dark brown over the older portions of the colony^ 

 and paler over the younger parts. 



