REPORT ON THE HEXACTINELLIDA. 105 



verse bundles, wliicli run irregularly ami usually form anastomoses ; the dermal ostia 

 are usually irregularly distributed between them. At the uppci' end is a strongly 

 injured sieve-like plate wliicli is not so distinct from the tissue of the wall as in 

 Euplectella. This trabecular network seemed to Marshall to consist of unsoldered 

 spicules. The loose mass of spicules lies on the inner side of the lattice, and consists of 

 uniaxial spicules 1 to 10 mm., long, slender daggers, weak five or six-rayed forms with 

 irregularly developed rays, very small spicules with several rays (three to six), spicules 

 with compressed rays and similarly formed diacts which are like a compass needle. 

 Hexacts with axes, from 0'2 to 0'3 mm. long, which bear at the end of each ray an 

 umbel with seven rays, are especially characteristic. Finally, there were found five- 

 rayed spicules and floricomes which could not be distingaiished from those of 

 Euplectella. 



Genus 3. Dictyocalyx, n. gen. 

 This genus contains only the one species, Dictyocalyx gracilis. 



Dictyocalyx gracilis, n. sp. (PL XII. figs. 1-7). 



The framework of siliceous beams, which is shown in its natural size, from, a 

 photograph, in PL XII. fig. 1, was trawled in the South Pacific (lat. 22° 21' S., long. 

 150° 17' W.) from a depth of 2385 fathoms, and a red clay bottom (Station 281). 

 From a compact conical basis, which has been attached to some solid body by a basal 

 surface of 5 mm. in breadth, and which is narrowed upwards to a diameter of 3 mm., 

 there arises an irregular retiform framework of beams, resulting in a cup-like form, 25 mm. 

 in length, and about 18 mm. in width above. One of the sides appears to have opened 

 inferiorly, and to have been again closed above. 



The beams of this framework, where they spring from the massive base, measure 

 from 2 to 3 mm. in thickness, but become thinner upwards by gradual ramification. 

 They consist of greatly jirolonged spicules, which vary in the number of their rays, but 

 which are for the most parts diacts, cemented externally in a cpiite irregular fashion. In 

 the meshy conical basal portion numerous hexacts occur, soldered between the larger 

 beams. 



After a more careful examination of the entire specimen I detected in various places, 

 but especially at the points of union of several intersecting beams, small patches of an 

 adherent soft substance which partly covered the beams. Although such insignificant 

 remnants of the soft body were no longer available for sections, it was still possible to 

 detach them in small fragments from the lattice-like framework, and to detect in them a 

 number of isolated spicules, which throw at least some light on the true character and 

 systematic position of the sponge. 



(ZOOL. CHALL. EXP. — PAHT LIII. — 1886.) Ggg 14 



