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



with a fuunel-sliaped expanded principal tube, and several lateral tubes 3 mm. in breadth. 

 The dictyoual framework of this sponge exhiljits beams which have a slightly tuberculated 

 surface and no sharply diflfcrentiated or slightly thickened crossing knots. In addition 

 to the hypodermalia and hypogastralia, which do not differ essentially from those of 

 Eurcte farrcopsis, scopulse occur. These have straight, unbroken, rough terminal rays 

 which are of a thick club- or knob-like shape. The uncinates are of various thickness, 

 but in most cases they are quite slender, and do not always stand at right angles to the 

 surface of the tube. Simple hexacts occur which are partly free and partly fused together 

 in various numbers. In contrast to Eurete carteri and Eurete marshalli, the great 

 abundance of oxyhexasters is particularly characteristic of the species. They possess 

 simj)le cylindrical principal rays, which are twice as long as the four greatly diverging 

 conical terminals, which are arranged in a cruciform manner on the extremity of each of 

 the principals (PI. LXXIX. fig. 13). 



I shall further add a short note in regard to a species described by Semper, which 

 presents some peculiarities worthy of notice. 



Eurete simplicissima, Semper, 



The beautifully developed network of tubes which Semper procured from Zebu, and 

 established as the basis of the genus Eurete, has been carefully described and figured 

 (two-thirds natural size) by Marshall.^ This specimen was kindly lent to me for 

 comparison by Professor Semper, but the remnant was unfortunately too utterly 

 macerated. With the exception of some parenchymalia (oxyhexasters with long thin 

 terminals), no free spicules were to be found. The dictyonal framework is composed of 

 smooth or slightly spinose beams, without any marked thickening at the nodes of 

 intersection, and exhibits so few characteristic peculiarities that it is difficult or 

 imjDossible to distinguish it from that of the other species. 



I am not in a position to say whether one of the species described may not be 

 identical with Eurete sim2)Ucissvma, Semper. It was suggested by the structure of 

 the oxyhexasters found in the base of an attached Actinia-like Anthozoon, that Eurete 

 $imiilicissima resembles my Eurete marshalli, which is figured in PI. LXXIX. figs. 1 to 4. 

 But since the dictyonal framework of this last sisecies is provided with thickened and 

 spinose nodes of intersection, the resemblance is not complete. 



1 Zeitschr. f. wiss. ZooL, Bd. xsv., Suppl., pi. xii. 



