484 ME. S. O. RIDLEY ON THE GENUS DIRRHOPALUM. 



Main skeleton. — Spiculo-fibres containing a large proportion of 

 pseudo-keratose ; the primary fibres at right angles to surface, 

 containing a single row of large, smooth acuate spicules (1), sur- 

 rounded irregularly by two or three rows of shorter acuates 

 (2), slightly spined basally, whose points project to the sides ; a 

 distinct margin of ceratinous material lies outside most of the 

 spicules. The secondary fibres are numerous, irregular, formed 

 of pseudo-ceratinous material, surrounding and showing distinct 

 margins outside the dumbbell spicules (3), which occur, one or 

 two together, in each fibre ; secondary fibres about one spicule in 

 length. Eine spinulate or supra-basally spinulate spicules (4) 

 (probably young forms) scattered over primary fibres. 



Dermal skeleton indefinite ; consists of a reticulation of the 

 dumbbell spicule, with the spinulates (4) scattered through it, 

 perforated at intervals by the terminal long acuates (1) of the 

 primary fibres. 



Pseudo-ceratinous material dense, pale amber-yellow. 

 Sarcode very slightly granular, of almost the same colour. 

 Skeleton- spicules. — (1) Strong, smooth, slightly curved acuate, 

 tapering to rounded base from a point at about 3 diameters from 

 it and to sharp point from same place ; size "5 by 025. (2) Smaller 

 acuate, slightly curved, slightly constricted immediately above 

 and very slightly microspined upon the base, and tapering to sharp 

 point from just above the constriction ; size '2724 by *0174. 

 (3) Dumbbell spicules ; shaft decidedly curved, and generally 

 very sparsely microspined ; ends well spined, separated from 

 shaft by slight constriction ; of about same diameter as middle of 

 shaft ; size 477 by -0158 millim. 



Flesh-spicules. — (4) Long, straight, spinulate spicules, or with 

 head just above base : various in size, viz. '19 by -0021 to 36 by 

 '00475 millim. Probably young forms of skeleton-spicules. (5) 

 Fine, decidedly tricurvate acuate, bow-shaped, tapering to fine 

 points from middle, smooth ; size "06334 by *0021. (6) Equi- 

 anchorates, bipalmate, navicular ; shaft almost straight ; length 

 '019 millim. 



Hah. Bay of Islands, north-eastern extremity of New Zealand 

 (Antarctic Expedition). Depth ? 



Examined in spirit and mounted in balsam from spirit. 

 Obs. One chief mass, 48 millim. long, with about eight branches 

 given off* at sharp angles from the single stem, and three or four 

 fragments of similar character, all more or less growing over the 



