with descriptions of some new genera. 403 



inosculating in every direction without order. Fibre solid, cylin- 

 drical, without spicula, with the exception of a few large com- 

 pressed fibres, which contain them in the centre. Investing 

 membrane thin, pellucid and simple. Interstitial substance ge- 

 latinous, containing siliceous spicula. 



There are many of the Spongiada which approach very closely 

 to the true Spongia in the external appearance of the skeleton 

 and in many of the prominent generic characters, but which 

 nevertheless vary in their structural peculiarities in so marked 

 and decided a manner as to render it advisable to arrange them 

 in other genera, and foremost among these stands the group of 

 which Spongia fistularis, Lamarck, is the type, and which I pro- 

 posed in my former paper to make the type of a new genus, and 

 to designate it Fistularia ; but upon reconsideration I find, that 

 although a most appropriate designation for the proposed genus, 

 it has already been applied as a generic term in botany, so that it 

 were better to abandon it altogether and to adopt another name, 

 which, although it may not be so expressive of the leading cha- 

 racter of the genus, will be more distinctive as regards other ge- 

 nera j and as I have been in a great measure indebted to my 

 friend Dr. Veronge for a correct knowledge of this very inter- 

 esting natural group of the Spongiada in the condition in which 

 they exist in their native element, I shall be doing but an act of 

 justice in commemorating his exertions in the cause of science by 

 naming it in honour of him, and the following I propose as the 

 characters of the genus 



Verongia. 



Gen. Char, Skeleton composed of a network of keratose fibres 

 inosculating in every direction without order. Fibre cylindrical, 

 continuously fistular, without spicula. Cavity of the fibre simple. 



The external character of the fibre of this group is widely dif- 

 ferent from that of the great mass of the true Spongia. While 

 in the latter they are usually flexible, fine in texture, and of a 

 colour approaching to light amber ; in the former, on the con- 

 trary, the fibre is rigid, coarse in texture, and very deeply co- 

 loured. The great central cavity of the fibre usually occupies 

 about one-third of its diameter, but in some species it is of much 

 larger dimensions. It is generally nearly uniform in its size in 

 all parts of the same species, but occasionally it dilates consider- 

 ably for a short space and then resumes its original diameter. It 

 is also usually somewhat increased in its dimensions at the ana- 

 stomosing portion of the fibre, as shown in PI. XIII. fig. 7, which 

 represents a piece of the fibre at one of the anastomosing points, 

 seen with a power of 100 linear. 



The great central cavity is lined with a thin pellucid mem- 



