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



12 mm. in its greatest diameter. The narrower upper end bears the circular opening of 

 the simple gastrie cavity, which is G mm. in diameter, and 10 mm. in depth. The body- 

 wall, which is iuferiorly from 3 to 4 mm. in thickness, becomes very gradually attenuated 

 upwards to the narrow smooth border. It is impossible to tell whether this oval body 

 was fixed upon a stalk, since the inferior extremity is greatly triturated. 



Most of the somewhat thickly crowded parenchymal spicules are straight diacts of 

 variable length and of moderate thickness. They usually exhibit on either end a 

 slender olive-like thickening, which is beset with small points and prongs. Such 

 irregularities also occur where the thickening is absent, on the simple rounded ends 

 (PI. XXIII. fig. 7). In the middle the rods exhibit either four cruciately disposed 

 tubercles (PI. XXIII. fig. 6) or a circular wreath. Less frequently the central swelling 

 is insignificant or entirely absent, and the central portion appears often to be marked 

 only by the intersection of the axial canals. Between the very irregularly disposed 

 diacts, which lie, however, for the most part parallel to the oiiter surface, there occur 

 moderately large, usually radially disposed hexacts, whose rays run out to points for a 

 greater or less distance, and are frequently beset with pointed tubercles, either aU over 

 or at the extremities (PL XXIII. fig. 5). 



Besides these principal spicules numerous rosettes occur in the form of discohexasters 

 with six, eight, or more similar thin diverging terminals on eveiy principal ray. The 

 watch-glass-like bent terminal disc of every terminal ray runs out into six or more 

 pointed marginal prongs (PL XXIII. fig. 3). 



The dermal skeleton includes strong pentact hypodermalia ; I have not, however, 

 seen either these or the autodermalia in situ. The latter are hexact piuuli in which the 

 thicker oval distal ray, which resembles a fir cone, is beset all round with scaly prongs, 

 while the proximal and the four transverse rays are smooth up to the pointed roughened 

 extremities (PL XXIII. fig. 4). 



The hypogastralia resemble the hypodermalia ; the autogastralia diifer from the 

 autodermalia in this, that their freely projecting ray is narrower and longer than in the 

 latter (PL XXIIL fig. 2). 



Genus 3. Balanites, n. gen. 

 Containing only one species. Balanites pipetta. 



Balanites pipetta, n. sp. (PL XXIII. figs. 9-14). 



The single specimen, which resembles a clay pipe or cigar holder, and which is 

 figured in PL XXIII. fig. 9, was trawled in the Antarctic at Station 157 (lat. 53° 55' S., 

 long. 108° 35' E.), from a depth of 1950 fathoms, and a Diatom ooze bottom. The oval 

 body, which measures 5 cm. in length and 1'5 cm. in thickness, is continued by a 



