REPORT ON THE HEXACTINELLIDA. 401 



skeleton there are scopulse of the ordinary type, some of which bear four uniformly thick 

 and barb-beset prongs without marked terminal swelling, while others exhil)it six thin, 

 smooth, slightly S-shaped prongs, with minute marginally-toothed terminal discs. In 

 the gastral skeleton I found no pentacts, or indeed any hypogastralia, except simple 

 scopulse in their usual position, with four uniformly thick, barb-beset, unknobbed prongs. 

 Little Ki Island, 140 fathoms. 



Genus 3. Fieldingia, Sav. Kent. 



With the single species, Fieldingia lagettoides, Sav. Kent. 



An irregular round, sometimes almost spherical body, which is usually ensheathed in a 

 thin parallel enveloping capsule, and traversed internally by an irregular framework of thin 

 round strands, which exhibit numerous spherical compact knots, about 1 mm. in diameter, 

 and occurring at distances of 2 to 3 mm. While the thin strands consist of a few long 

 beams, beset with small, scattered and pointed tubercles, the spherical knots are formed of 

 a thick framework of beams with a similar superficial appearance. Both the large, more 

 or less elongated, and the short reticulate beams of the spherical knots have abundant 

 small rough hexacts soldered on to them, usually at right angles. These doubtless serve 

 to enlarge or thicken the dictyonal framework. The leaf-like enveloping capsule which 

 surrounds the larger portion of the sponge, consists of pentacts bound together in plates 

 by a narrow-meshed network of syuapticula extending in the tangential direction. The 

 parenchyma contains, besides long uncinates and simple small hexacts, oxydiacts with 

 central nodes and sharpened extremities, oxyhexasters with very short, in some cases 

 almost undeveloped principals, and long smooth terminals, and also discohexasters with 

 short principals and rather long, slightly curved terminals. The dermal skeleton 

 contains, besides the above-mentioned pentacts, scopulse with four uniformly cylinfh-ieal, 

 slightly divergent prongs, which are wholly covered with barbs, but exhibit no terminal 

 swelling. Portugal, 500 fathoms ; Little Ki Island, 140 fathoms. 



Genus 4. Sclerothamniis, W. Marshall. 



With the single species Sclerothamnus clcmsii, W. Marshall. 



A shrub-like, dichotomously branched stock, with long, round, and terminal Invinches 

 as thick as a little finger, and Ijearing spiral or annular pads a little finger's breadth 

 across, and alternating with somewhat narrower grooves. The somewhat thick dictj'^onal 

 framework supporting the body consists of beams which enclose predominantly rectangular 

 meshes, and exhibit superficially numerous small, irregidarly scattered, wart-like and 

 pointed tubercles. They are united without nodal thickening. While the main strands 

 of fibres in the axis of the branches lie longitudinally, ''•<'■, parallel to the axis, in the 



(ZOOL. CHALL. EXP. — PART LIII. — 1887.) Ggg 51 



