142 CHONELASMA. 



These skeleton-nets may have belonged to a euretid sponge. They are 

 similar to those described above from Station 4651. 



COSCINOPORIDAE Zittel. 



Lamellar, calyculate, or more complicated Hexasterophora consisting, if 

 lamellar, of a simple plate; if calyculate or more complicated, of a rather thin 

 wall enclosing a wide cavity. This plate or wall is traversed by straight, conical, 

 blindly ending, sac-shaped afferent and efferent canals. With a firm supporting 

 reticulate skeleton and uncinates and scopules. 



The collection contains one specimen of this family, which belongs to a 

 species of Chonelasma. 



CHONELASMA F. E. Schulze. 



Funnel-shaped or lamellar Coscinoporidae. 



Chonelasma sp. 

 Plate 32, figs. 7-9. 



There is in the collection a rather large skeleton-net of this sponge, collected 

 in the Paumotu Islands at Station 3689 (A. A. 134) on 28 October, 1899; 18° 

 06' S., 142° 24' W.; depth 1476 m. (807 f.); they grew on a bottom of fine 

 coral-sand and manganese nodules; the bottom-temperature was 37.6°. 



This skeleton-net (Plate 32, fig. 7) is a curved plate, 92 mm. long, 51 mm. 

 broad, and 9-11 mm. thick. The sponge to which it belonged may have been 

 tubular or calyculate; probably it was of large size. The convex, probably 

 outer (dermal) zone of the skeleton-net (Plate 32, fig. 8) is on the whole smooth. 

 It is composed of skeleton-net lamellae vertical to the surface, extending in- 

 discriminately in all directions and crossing each other irregularly. These 

 lamellae form a network, the meshes of which are represented by short vertical 

 canals round or polygonal in transverse section and 0.5-2 mm. wide. The 

 concave, probably inner (gastral) zone of the skeleton-net (Plate 32, figs. 7, 9) 

 has some outgrowths. Most of these are quite small. One is 8 mm. high. 

 Apart from a curved, obliquely transverse band 3-5 mm. broad, where the net- 

 work is so dense as to appear nearly solid to the naked eye, the zone of the 

 skeleton-net bordering on this inner concave, probably gastral surface is com- 

 posed of skeleton-net lamellae, vertical to the surface and extending longitudi- 

 nally. These lamellae are about 0.7 mm. apart and connected by numerous 



