308 HYAIX)NEMA (OONEMA) BIANCHORATUM PI>iULINA. 



Hyalonema (Oonema) bianchoratum pinulina, var. nov. 

 Plate 82, figs. 1-34; Plate 83, figs. 1-68; Plate 84, figs. 1-32; Plate 85, figs. 1-8. 



Two fine specimens of this variety were trawled off the coast of northern 

 Peru at Station 4651 on 11 November, 1904; 5° 41.7' S., 82° 59.7' W.; depth 

 4063 m. (2222 f.) ; they grew on a bottom of sticky, fine, gray mud; the bottom- 

 temperature was 35.4°. In the following description one of them is designated 

 a, the other h. 



With other characteristics these sponges differ from the typical Hyalonema 

 {Oonema) bianchoraturn Wilson by the distal rays of their pinules attaining not 

 nearly so great a length. To this the name of the variety refers. 



Shape and size. Both specimens are upright, cylindrical, widened above 

 to form a shallow cup, and rounded at the lower end, from which a rather eccen- 

 trically situated stalk arises. From the bottom of the cup a cylindroconical 

 terminally rounded gastral cone protrudes. Specimen a is 111 mm. long, the 

 longest and shortest diameters of its upper end being respectively 49 and 31 

 mm. Specimen b (Plate 82, fig. 1) is 141 mm. long. The longest and shortest 

 transverse diameters of the central cylindrical part of its body are 49 and 42 mm., 

 those of its upper, cup-shaped extension respectively 66 and 48 mm. The 

 stalk of specimen a is broken off at a distance of 40 mm. from its point of origin, 

 that of b close to the body of the sponge. An isolated stalk, in the same jar 

 as the body of specimen b, which fits the stump at the lower end of the body, 

 apparently belongs to it. This stalk, which was attached to the stump before 

 the specimen was photographed (Plate 82, fig. 1), is 230 mm. long, and, near 

 its point of origin, circular in transverse section, and 3.8 mm. in diameter. 



Surface. Pores could not be found where the choanosome extends up to 

 the superficial membrane. These poreless tracts appear as broad bands which 

 form a network with irregular meshes, the maximum diameter of which is rarely 

 more than 1 mm. on the dermal face, but is sometimes as much as 10 mm. on the 

 gastral face. In the meshes of this primary network are spread out reticular siev^e- 

 membranes (Plate 82, fig. 1; Plate 83, figs. 60-62) composed of narrow bands 

 of superficial (dermal or gastral) tissue. The meshes of the dermal secondary 

 reticulations are usually 100-300 ^ wide, those of the gastral usually 300-500 /.i. 

 The nodes of these nets are much thickened. In the meshes of the dermal 

 pore-sieves (Plate 83, fig. 62) some remnants of what seems to have been a ter- 

 tiary network were observed. In the meshes of the gastral pore-sieves (Plate 

 83, fig. 61) no such remnants could be found. 



