292 THE VOYAGE OF H.M.S. CHALLENGER. 



lu the parencli}Tiia harpoons directed at right angles to the surface and hexasters of 

 various kinds occur in addition to simple hexacts. 



1. Eurete semperl, n. sp. (PL LXXVIL). 



Near the Little Ki Island (Station 192, lat. 5° 49' 15" S., long. 132° 14' 15" E.), 

 from a depth of 140 fathoms and a blue mud ground, the trawl brought up, among 

 numerous other Hexactinellids, that form of Eurete represented in PL LXXVII. fig. 1. It 

 was abundantly beset with small Actinise and exhibited in spirit a dull light grey colour. 

 Several solid basal pedestals, 5 to 8 mm. in diameter, partly united in a common basal 

 plate, bear a system of irregular reticulated and anastomosing tubes, 8 to 15 mm. in 

 diameter, and 1 to 2 mm. in wall's thickness. The free end is unfortunately broken off, 

 or more or less seriously injured. 



The basal pedestals are dead up to a level of about 10 mm., otherwise the stock 

 is tolerably well preserved. The strongly developed, somewhat irregular, dictyonal 

 framework, which only rarely exhibits square or rectangular meshes, consists of strong 

 beams beset with a few small spines, and united in thickened, spherical, swollen nodes of 

 intersection more or less thickly covered with strongly developed but low-set teeth 

 (PL LXXVII. fig. 2). The freely projecting spherical spinose bosses on the dermal 

 and gastral surfaces are remarkably short and stunted. In the inferior regions of the 

 stock the meshes of the dictyonal framework are very much narrowed by numerous 

 small apposed hexacts, which, becoming thickened and united all round, contribute to 

 strengthening the already existing framework. The result is the formation of a firm, 

 stony, finely porous mass. Superiorly, however, the meshes become wider. Afi'erent 

 canals traversing the wall at right angles to the surface, and corresponding efferent canals 

 are seen in the dictyonal framework as round passages which run alternately from the 

 outer and the inner bounding surface, and either end blindly or divide into lateral twigs. 

 The thicker the wall of the tube, the more is the canalicular system developed within the 

 dictyonal skeleton. The free parenchymalia are represented especially by small simple 

 regular oxyhexacts, present in extraordinary abundance, and thickly beset in every 

 region with minute pointed tubercles, so that they appear rough even under low power 

 (PL LXXVII. fig. 7). In almost any region of the dictyonal framework they become 

 reacbly fused to a ray perpendicular to the surface of the framework, or to one of the thick 

 nodes of intersection (PL LXXVII. fig. 8). There they become thickened by the apposi- 

 tion of concentric siliceous lamellae and also unite with other adjacent strands, thus 

 leading to the growth and thickening of the whole dictyonal skeleton. The size of these 

 rough hexacts varies greatly, but they rarely exceed 0'17 mm. in diameter. 



The uncinates, which are always disposed at right angles to the bounding surfaces, 



