REPORT ON THE HEXACTINELLIDA. 223 



the numerous tetraets, that the rays are somewhat curved, even in the cross plane (PI. XL. 

 fig. 12). The spicules of the basal tuft, which vary greatly in size, are smooth superiorly, 

 but inferiorly beset with isolated barbs, while the helmet-shaped thickened lower end 

 bears four long cruciate, flat or roundish, anchor teeth of variable length, directed upwards 

 and outwards (PI. XL. figs. 8, 9). 



G. Hycdonema [Stylocalyx) elegans, n. sp. (PL XXXL figs. 1-7). 



In the Mid Pacific, to the south-east of the Christina Islands (Station 271, lat. 0° 33' S., 

 long. 151° 34' W.), from a depth of 2425 fathoms and a Globigerina ooze bottom, an 

 extremely delicate and soft Hyalonema was trawled. The compressed roundish inferiorly 

 pointed body has a thickness of about 2 cm., and bears a basal tuft of a few projecting 

 spicules which measure 12 to 14 cm. in length (PL XXXL fig. 1). At the upper end of 

 the body a central cone slightly projects, and from it four cruciately disposed radial 

 plates extend, dividing the central cavity into four divisions. The superior openings 

 of these cavities are seen as irregular roundish gaps on the upper surface. It is 

 improbable that a terminal sieve plate extended over these apertures; no trace of such 

 a structure persists. On the upper half of the body, indeed, the whole outer skin seemed 

 to have been rubbed away, while traces of the same are still recognisable on the lower 

 somewhat bulging conical portion. 



The loose parenchyma contains not only simple smooth medium-sized oxyhexacts, 

 and numerous smooth (or rarely terminally roughened) (PL XXXL fig. 3) oxydiacts of 

 medium size and inconsiderable length, but also a great number of small smooth oxy- 

 hexacts with curved rays. 



The dermal skeleton (PL XXXL fig. 2) consists of somewhat strongly developed, 

 smooth oxypentacts, on which numerous autodermal pentact piuuli are apposed. The 

 latter exhibit four moderately long, terminally slightly toothed basal rays, and a more 

 or less spinose distal (PL XXXL fig. 4) which may attain a length of 0"5 mm. Besides 

 these, numerous medium sized eight-rayed amphidiscs occur, bearing on their axial rod 

 several somewhat irregularly distributed boss-like, projecting, lateral tubercles, and 

 exhibiting straight, bell-shaped terminal umbels which are so long that their flat lancet- 

 shaped rays almost meet one another (PL XXXL fig. 6). There are also numerous 

 minute amphidiscs with slightly arched short umbels, 0"02 to 0'04 mm. in length 

 (PL XXXL figs. 5, 7). Isolated large broad amphidiscs also occur, but I am doubtful 

 whether they really belong to this species. From their scarcity and irregular disposition it 

 seems probable that they owe their origin to one of the other species of Hyalonana which 

 lay in the same glass and which contain these broad amphidiscs in abundance. The 

 basal tuft exhibits numerous firm spicules with six to two rays, which are straight and 

 terminally beset with strong teeth, or else truncated or rounded. 



