THE SPONGES. Ill 



STELLETIDAE SoIIas. 

 Penares Gray. 



1867. Penares Gray, 1867, p. 542. 



18S8. Fapijnda O. Sclim., Sollas, ISSS, p. 198. 



1891. Penares Gray, Vosmaer, 1891. 



1894. Ecionema pars Lendenfeld, ] 891, p. 97. 



1894. Penares Gray, Topsent, 1894, p. 356. 



1900. Penares Gray, Tbiele, 1900, p. 21. 



1903. Ancorina O. Schm. subgen. Penares Gray + Pnpi/rula O. Sohm., Lendenfeld, 1903, pp. 60, 69. 



Penares foliaformis, sp. nov. 



Plate 15, Figs. S-11. 



Diagnosis. Entire body probably massive, with curved surface. Oscula ? Cladomes 

 of the dichotriaenes divide the surface into pore areas, about 0.75 mm. in diameter. In 

 each pore area usually a single pore, opening into a short radial pore canal, which connects 

 with a subspheroidal subdemial chamber. Flagellated chambers aphodal. Ectosome 

 collenchymatous, and containing many fibre cells arranged tangentially. Megasderes. 

 Dichotriaenes, varying toward triaene condition, with flattened, irregular, leaf-like cla- 

 domes, form a single layer at the surface. Oxeas, singly and in loose sheaves, in paren- 

 chyma; for the most part more or less radially arranged. Microscleres. Microrhabds of 

 oxeate character, but with rounded ends, 160 x 8 /;t to 60 x 5 /x ; very abundant in the 

 superficial layer of the ectosome. Oxyasters, 16-24 /x in diameter, in canal wall and 

 intervening parenchyma. 



Station SJfl4, 1 specimen. 



The single specimen is a small, well-preserved fragment (Fig. 7, Plate 

 15), including the surface and part of the interior. The surface has a 

 spheroidal curvature, and the fragment a greatest thickness of 9 mm. 

 The surface is hard, stony, and whitish-brown ; the interior dense, firm, 

 and slightly darker in color. The piece includes no oscula, and the shape 

 of the entire sponge is problematical, although probably massive, with 

 curved surface. 



To the eye, or with a lens, the surface appears divided into minute 

 polygonal areas about 0.75 mm. in diametei'. These are the pore areas, 

 which have a whitish appearance in the alcoholic specimen. Thej' are 

 separated by narrow, darker-looking bands, which represent the reticulum 

 formed by the tangential rays of the dichotriaenes. Minute dark points 

 are visible scattered in the dark bands, and less distinctly in the whitish 

 areas. In the former they represent the points of union between the 

 rhabdome and cladome of the triaenes. In the latter place they are actual 

 apertures, the pores. 



