70 THE VOYAGE OF H.M.S. CHALLENGER. 



in the form of three elongated stalks connected together at their bases. I do not think 

 that this difference in external appearance can justify the establishment of two varieties ; 

 for in the structure of their soft parts (quite identical -ftdth that of Aplysina), and again 

 in that of the skeleton, the specimens do not differ at all. Indeed the colour of the 

 parenchyma in one case (massive specimen) is rather yellow, in the other greyish, but I 

 am not inclined to ascribe any consequence to this difference. Both the specimens are 

 represented on PI. IX. I have nothing further to add to this illustration, and as to the 

 properties of their skeleton in general and to those of their skeletal fibres I refer the 

 reader to page 7 of this report. 



Colour. — Outer surface greyish, parenchyma yellow and dirty greyish-white, skeletal 

 fibres brownish-yellow and brownish. 



Habitat.— ^iAtion 177, August 18, 1874, off Api, New Hebrides; depth 60 to 70 

 fathoms. Off Tahiti ; reefs; September 1875. 



Verongia, Bowerbank. 



Aplysinidae, the central axis of whose thick-walled skeletal fibres is readily to be 

 distinguished optically from the surrounding horny walls. 



Verongia hirsiita (?), Hyatt (PI. X. figs. 1-3). 



Verongia hirsuta, Hyatt, Eevision, &c., vol. i. p. 403. 



I leave to later investigators the decision of the question whether the form I am 

 going to describe is identical with Verongia Jdrsuta, var. Jistularoides of Hyatt. 

 His description is very short, and there are no explanatory illustrations ; it agrees, 

 however, closely with what I can give of the form in cjuestion. I myself indeed 

 should call the meshes of the skeleton regular, but wath regard to this difference the 

 utmost caution is advisable. In Verongia Jistularis [Spongia Jishdaris, Linnd) from the 

 Museum of Erlangen, which both Hyatt and myself were able to obtain for the purpose 

 of comparison, and which is placed by Hyatt in his family Dendrospongiadae, 

 characterised inter alia by irregularity of the meshes, I was able to discern meshes of 

 a geometrically regular polygonal character, and again meshes sometimes of irregularly 

 round, sometimes of irregularly oval, shape. 



As to the anatomy of the form, I am glad to confirm the supposition of Vosmaer ^ 

 that it does not differ from that of Aplysina; the exposition of the canal-system 

 on PL X. fig. 7 has been made after a preparation of Verongia tenuissima, but it may 

 be applied also to Verongia hirsuta, the more so as both the specimens of Verongia 

 hirsuta and Verongia tenuissima, represented in the collection each only by a single 



' On Vclinea gracilis, p. 444. 



