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



wide ramifying tubes wliicli open into the fistulte. Surface, very uneven, covered with 

 numerous bladder-like, almost glabrous swellings. The whole much encrusted with foreign 

 organisms, Serpulas, Polyzoa, Sponges, &c. 



Skeleton. — Arranged as in Rhizochalina fistulosa into (a) a dermal network of has- 

 tately-pointed oxeote spicules, not very closely aggregated, and (6) a rather delicate reticu- 

 lation of spiculo-fibres, forming subequal polygonal meshes (the bast-layer), the fibres com- 

 posed of oxeote spicules similar to those of the dermal layer, (c) A fairly close reticulation 

 of stouter fibres filling up the interior of the sphere, and composed of spicules like those 

 of the dermal layer, with, as usual, numerous unattached spicules lying between the fibres. 



Spicules. — Hastately pointed oxea (PI. IX. fig. 1), slightly curved and abruptly, but 

 fairly sharply, pointed, measuring about 0'195 by 0"013 mm.; size and shape very 

 uniform throughout. 



The rind, composed of the dermal membrane and the subjacent bast-layer, is much 

 more firmly attached to the underlying tissues in this species than in, for example, Rhizo- 

 chalina jyedunculata (below). At the ends of the fistulse (PL IX. fig. 7) the arrange- 

 ment of the dermal spicules is difi'erent to what it is on the body (as shown in the figure). 



These large specimens present many features of great interest. The one figured 

 (PL VIII. fig. 5) is firmly attached to a slab of rock by one side. There is a very distinct divi- 

 sion into upper and lower surfaces, the fistulse being chiefly confined to the upper surface. 



We at first identified this well-marked form with Alcyonium putridosum, descril^ed 

 by Lamarck {loc. cit.) from Australian Seas ("port du roi Georges"). There can be no 

 douljt that Lamarck's Alcyonium pxitridosum is some species of Rhizochalina, and that 

 it is nearly allied to Rhizochalina p)utridosa, but as there is not sufiicient evidence to 

 make the identification a certainty, we have given the synonym with a query. 



Localities.— Station 162, April 2, 1874; lat. 39° 10' 30" S., long. 146° 37' E. ; 

 Bass Strait ; depth, 38 fathoms ; bottom, sand and shells. Three large specimens. 



OffPort Jackson, 30 to 35 fathoms. One large specimen. 



Off Bahia, 7 to 20 fathoms. Some fragments of fistulse, which seem to be referable 

 to this species (?). 



Habitat. — Australian Seas (Challenger) ; off Bahia (Challenger). 



Rhizochalina singaporensis. Carter, sp. 



1883. PhlceoiUcfyon singapcyrense. Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. xii. p. 326, 



pL xiii. fig. 17. 



1884. Rhizoclialina singaporensis, Kidley, Zool. Coll. H.JI.S. "Alert," Erit. Mus., p. 421, 



pi. xli. fig. «. 



With this species we identify a single fistula, in a bad state of preservation and of 

 doubtful locality. The species is described by Carter (loc. cit.), and with only a fragment 

 before us it does not seem ad^dsable to go into further details. 



