564 STUDIES ON SPONGES, 



Colour. 



The colour in the living state is a very bi'ight red, similar to 

 Rosanilin-red. In spirits the sponge becomes pale flesh-coloured, 

 and dried it appears brown. The spirits extract a deep orange- 

 coloured pignut, very similar to that extracted by spirits from 

 many other Monactinellidae. 



Surface. 



The surface is reticulated throughout in a very regular and 

 uniform manner, and appears thereby similar to Bowerbank's 

 Raphyrus Griffithsi, and also to some species of Halme among 

 horny sponges. Young and old specimens always show the same 

 reticulation on the surface, there seem never to be Papillie in the 

 place of the meshes, as it is the case in young specimens of the 

 genus Papillina (O. Schmidt), which, according to that author, is 

 identical with Raphyrus. As stated above, however, I consider 

 these genera distinct. 



The reticulation is produced by a very regular network of ])Y0- 

 jecting lines on an average 2 mm. wide. In the meshes between 

 these there are slight depressions, about 4-6 mm. deep. The 

 meshes themselves have a width of 3-4 mm. The membrane 

 which is thus expanded below the sui-face in the meshes is very 

 soft, whereas the projecting lines are exceedingly hard. This 

 membrane is also slightly concave. In it we find very small pores 

 in groups, which are the commencement of the inhalent system. 



This network covers the whole of the surface of the sponge 

 and extends downwards into the conic pseudoscular tubes to their 

 bottom. 



Oscula are found scattered irregularly over the whole of the 

 surface; they are circular and measure from 2-10 mm. in 

 diameter. These oscula are as freqvient on the exposed parts of 

 the sponge as in the sides of the conic pseudoscula. 



