from the N.W. Coast of Spain. 105 



charged, but also the spongozoa whicli now and then appear in 

 groups with portions of tlie sponge placed under the microscope 

 for examination (as may be seen by reference to PL Yll. 

 fig. 12), pointing out the interesting fact that the kerataceous 

 sponges possess the same kind of spongozoon as the rest. 



Aplysina co7'neosteUata, n. sp. PI. VII. fig. 1. 



Sessile, spreading, massive, rising into short lobes terminated 

 by mammiform conical extremities, each bearing a large vent 

 (fig. 1, h b] 2, b). Colour pinkish violet or flesh-colour. 

 Surface smooth, minutely aculeated, each aculeation (fig. 2, a) 

 terminated by the projection of a single horny hair-like fila- 

 ment (fig. 3,rt). Internal structure cancellous, fleshy, permeated 

 by branched systems of excretory canals, which finally end 

 in the large vents at the summits of the mammiform eminences 

 respectively ; the whole supported on a horny skeleton com- 

 posed of 5-6-rayed stclliform structures (fig. 4, ccccc), one 

 arm of which, when near the surface, projects through an 

 aculeation (fig. 3, ac), and the rest, where they are in contact 

 with the rays of neighbouring stellates, united to the latter by 

 a thin expansion of transparent horny matter (fig. 4, ddd)^ 

 which thus, altogether, forms a continuous skeleton supported 

 or a few stem-like filaments at the base, which are united to 

 the object on which the sponge may be growing (fig. 4, b b b). 

 Horny filament hollow, the core consisting of fine granular 

 matter only^ with here and there parabolical wave-like lines, 

 whose convexities are directed towards the end of the filament 

 (figs. 5 & 6) ; diameter of the core much exceeding the thick- 

 ness of the horny tube (fig. 7). 



Dermal structure consisting of a thin transparent layer of 

 sarcode (fig. 3, c; 9, a a), iuAvhich the pores maybe observed 

 by the aid of a microscope to be situated in variable plurality 

 over the interstices of a subjacent network (fig. 8, a, J ; 9, c) 

 composed of elongated fusiform granuliferous cells adhering 

 together in a cord-like form (fig. 10, Z?), which contrasts strongly 

 with the globular form of the granuliferous cell in the overlying 

 dermal sarcode (fig. 11) ; both structures covering the whole 

 of the sponge up to the brink of the vents, and by their transpa- 

 rency exposing the cavities of the cancellous structure beneath, 

 whose dark round cavities thus appear like so many minor 

 vents opening upon the surface generally. 



Body charged with spherical ova (fig. 4:^ g g g) of a deeper 

 colour than the rest of the substance, presenting on pressm'e 

 under the microscope a homogeneous, transparent, capsular 

 envelope, within which is a more delicate one filled Avith nucle- 

 ated granuliferous cells suspended apparently in a grumous 



