

" '•' ■'- — ■ 



128 



THE SPONGES. 



Carter, Oceanapia Norman, and that the group, moreover, is heterogeneous. 



* ■ 



He proposes therefore to give up the group, and to assign Rhizochalina to 

 the Chalininae, Phloeodictyon to the Renierinae, Oceanapia to the Gelliinae. 

 In this report I conceive the genus in the sense of Dendy. 



Oceanapia bacillifera, sp. nov. 



Plate 17, Fig. 8 ; Plate 18, Figs. 2-4. 



Diagnosis. Only the fistulae known. These are yellowish-brown tubes, 50-80 mm. 

 long and 8-12 mm. in diameter, with unobstructed cavity. Wall of fistula dense and. 

 firm, 0.5 to 2.5 mm. thick, with smooth outer surface and nearly smooth inner surface. 



Spicule, a 'smooth, cylindrical, distinctly curved strongyle, 360-380 /x x 24 p. Wall 



of the fistula almost entirely filled with a dense skeleton, the greater part of which forms 

 a vague reticulum, consisting of wide, loose spicular tracts, which bound small, rounded 

 meshes. Spicules united by considerable spongin, and arranged tangentially to the sur- 

 face of the sponge. In the innermost layer of the wall a few long spicular tracts occur. 

 These give rise to a reticulum with long, narrow meshes, — meshes elongated in the 

 direction of the long axis of the fistula. At the outer surface skeleton not reticulate, 

 spicules here lying side by side, in any particular region parallel to one another. 



Station SJfiJf^ two specimens. 



Both specimens are fragments, including only the fistulae. These are 

 yellowish-brown tubes (Fig. 2, Plate 18), somewhat curved, and show- 

 ing here and there low irregular protuberances, or ridges. The tubes are 

 open at both ends, the larger measuring 80 mm. in length, with a trans- 

 verse diameter of about 12 mm., the smaller 50 mm. in length, with a 

 transverse diameter of about 8 mm. The wall is very firm and dense. 

 Throughout the greater part of the larger tube it is extremely thin, 

 0.5 mm. thick, although in spots, especially near one end, it attains a 

 thickness of 2.5 mm. In the smaller specimen the wall is thicker, 



i 



the thickness ranging from 0.75 mm. to 2.0 mm. In both specimens 

 the cavity of the tube is unobstructed, the outer surface quite smooth, the 

 inner surface somewhat less so, and showing closely set whitish lines which 

 course longitudinally, and, anastomosing, form a reticulum with narrow, 

 elongate meshes. These lines represent the innermost layer of the skeletal 

 reticulum. 



No dermal membrane is present, the superficial layer of spicules being 

 quite bare (surface view, Fig. 8, Plate 17), except in spots, where they 



are covered by exceedingly thin patches of an incrusting 



species 



of 





