220 HYALONEMA (HYALONEMA) SP. 



covered with conspicuous recurved spines; by the micramphidisc being longer 

 and having much larger anchors than in H. (H.) tenuifusum, .and being shorter 

 and having relatively much broader anchors than in H. (H.) tylostylum, and by 

 other characters. These facts together with the widely separated habitats (fully 

 50 equatorial degrees) are sufficient for specific separation. 



Hyalonema (Hyalonema) sp. from Station 4656. 

 Plate 68, figs. 26-33; Plate 69, figs. 1-5. 



Part of a macerated specimen was trawled off northern Peru, Station 4656, 

 on 13 November, 1904; 6° 54.6' S., 83° 34.3' W.; depth 4063 m. (2222 f.); 

 the bottom was composed of fine, green mud mixed with gray ooze; the bot- 

 tom-temperature was 35.2°. It is obviously the basal part of a Hyalonema but 

 cannot be determined specifically. 



The specimen (Plate 68, fig. 26) is an elongate, irregularly oval lamella 

 60 mm. long, 22 mm. broad, and 8 mm. thick. A stalk 5 mm. thick and broken 

 off short arises from one of the two narrow ends. The colour is brown. 



Amphiox megascleres, basal acanthophores, stalk-spicules, and microhexac- 

 tines, which doubtlessly belong to the sponge, are found in large numbers in the 

 spicule-preparations. Only a few hexactine and pentactine megascleres, pinules, 

 and amphidiscs were seen. Some of these are probably proper to the sponge, 

 others foreign, and it is impossible in every case to determine with certainty. 



The pinules which seem to be proper to the sponge are of two kinds, larger 

 and smaller. Both are pentactine. The larger have a bushy distal ray 460-540 ^ 

 long and 8-10 /x thick at the base. The distal ray, together with the spines, 

 is 40-60 n in transverse diameter at the point of maximum thickness, which lies 

 high up. The lateral rays are 50-73 /x long. The dimensions of the smaller 

 pinules (Plate 69, figs. 1, 2) are: — distal ray, length 124-360 m, basal thickness 

 7-12 n, maximum thickness, together with the spines, 15-43 /n; lateral rays, 

 length 27-50 m- 



A pentactine observed has conical lateral rays 750 ^ long and 35 fi thick 

 at the base. 



The hexactines are 0.7-1.5 mm. in maximum diameter. The rays are 

 16-28 fi thick at the base, and usually somewhat unequal in size in the same 

 spicule. 



The amphioxes are 1.3-2 mm. long and 10-17 m thick near the centre. Most 

 of them are distinctly centrotyle. The central tyle is generally about 5 jj. more 

 in transverse diameter than the adjacent parts of the spicule. 



