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



Suberites caminatus,^ Ridley and Dendy (PI. XLI. fig. 2 ; PI. XLV. figs. 5, 5a, 5b, 



5c, 5d). 



1886. Suhei-ites caminattcs, Eidley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, vol. xviii. 



p. 484. 



Sponge (woodcut, Fig. 7) massive, roughly hemispherical, sessile, corticate, resembling 

 in shape and size Esperella mammiformis, nobis. The single specimen in the collection 

 is attached by a broad base to an empty Brachiopod shell and 

 terminates in a single oscular projection at the apex. The base is 

 not round but oval, and the longer diameter measures 19 mm., 

 and the shorter about 13 mm. Height of sponge about 13 mm. 

 Colour in spirit light, greyish-yellow. Texture very firm, hard 

 and compact. Surface even, but very minutely hispid and rather 

 harsh to the touch ; also marked with shallow meandering and 

 Fig. 7.— Suberites cami- auastomosiug grooves, SO as to bccomc faintly tesselated. Osculum 



natus ; attached to a o o ■ <■ i 



Brachiopod shell; », [Ym. 7 o) siuglc, Small, tubular, at the summit oi the sponge. 



osculum. \ to ' / C5 ' ' ' _ X o 



Pores diflficult to make out, almost certainly in the shallow grooves 

 on the surface ; seen in section leading into elongated subdermal cavities between the 

 skeleton fascicles of the cortex. 



Skeleton. — There is a very dense and definite cortex (ectosome), about 0-63 mm. 

 thick, very sharply and suddenly marked ofli" from the underlying tissues and strength- 

 ened by closely placed fascicles of tylostylote spicules which extend right through it, 

 and have their points directed outwards, but projecting only very slightly beyond 

 the surface. The deeper skeleton is rather scanty and is composed of bands of spiculo- 

 fibre (formed of large tylostylote spicules), which run vertically towards the surface of 

 the sponge to join the cortical layer. 



Sincules. — Megasclera; of one form only, viz., smooth tylostyli (PI. XLV. figs. 5, 

 5a, 56, 5c, 5d). There are two chief sizes, the smaller ones occurring in the cortex and 

 the larger in the deeper skeleton ; there is great variability in size ; the spicules of the 

 cortex measure about 0-35 by 0-01 mm., they are stouter in proportion to their length 

 than are the spicules of the deeper skeleton, have well developed, roundedly triangular 

 heads and sharp points, and are often slightly bent. The spicules of the deeper skeleton 

 are very long, straight and slender, have rather less developed, pointedly oval heads, and 

 taper very gradually indeed to an extremely fine point at the apex; size about 1*2 by 

 0'017 mm. Intermediate sizes are abundant. 



This is a very pretty and interesting little sponge ; it may be recognised by its external 

 form, and more especially by the projecting, well-marked osculum. The form recalls some- 

 what Tentorium semisuberites. This and the further resemblance recorded in the variety 



' So called from the chimney-like osculum at the summit of the sponge. 



