AKT. 12 HEXACTINELLID SPONGES — OKADA 43 



Subtribe Scopularia F. E. Schulze, s. ext. 



Family EURETIDAE F. E. Schulze, s. ext. 

 Genus EURETE Semper, 1868 



EURETE NIPPONICA, new species 



Plate 3, Figure 3 



Among the specimens of Eurete collected, a single small injured 

 specimen (holotype, U.S.N.M. No. 22038) appears to represent a new 

 species. It was obtained at Station 4893 (10 to 20 miles southwest 

 of the Goto Islands, 106 fathoms). This small and erect sponge 

 arising from the slender tubular basal region measures 25 mm in 

 height and about 24 mm in breadth. At the upper end there are 

 irregular, radial tubes about 5 mm in diameter, most of which are 

 injured at the apertural margin. The soft parts are sufficiently pre- 

 served in places to enable one to recognize the microscleres. 



In spicular characters Eurete nipponlca closely resembles E. timr- 

 shalli, differing from it in the thickened spinose nodes at the inter- 

 sections of the dictyonal beams and in having onychasters in the 

 parenchyme. The onychaster may be considered as a derivative of 

 the discohexaster, though, as I have demonstrated, this form may be 

 derived from an oxyhexaster. 



The dictyonal net forms a regular to irregular triangular or quad- 

 rangular honeycomb. The beams composing it are nearly covered 

 with conically pointed small tubercles on the entire surface. Every- 

 where in the lower, older regions of the specimen the dictyonal 

 network forms a thicker layer. It is stronger and is covered entirely 

 with many more, stout tubercles. At the dermal and gastral margins, 

 on the surfaces bounding the honeycomb cavities, most of the nodes 

 appear distinct, round, and thickened, showing a strawberrylike 

 form, though much more prominently formed on the dermal than 

 on the gastral regions. 



The dermal membrane is supported by pentactins with paratangen- 

 tial Yixys, 160^ to 200;ii long, which are nearly straight or bent inward, 

 gradually attenuated toward the conically pointed or round ends, and 

 covered with microtubercles on the surface, being somewhat pro- 

 nounced at the ends. The proximal radial ray is somev/hat shorter 

 in length, is gradually attenuated to the slightly roughened, coni- 

 cally pointed end, and usually bears densely distributed, small 

 pointed tubercles. 



The gastralia are also pentactins, which show nearly the same 

 features as the dermalia, though they have more inwardly curved 

 tangential rays. 



