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



sharp spines; size, 0'91 by 0"29 mm.; I'l by 0'2 mm., in the middle 058 mm. between 

 the apices of the divergent processes. Double and quadruple structures, forming four to 

 eight-rayed stars, 0-28 mm. in diameter, or forming irregular, jagged, almost shapeless 

 calcareous bodies. 



In the polyp-bearing head-portion of the stem and in the branches the variously- 

 shaped spicules give place to spindles, which, at first placed transversely, in the twigs 

 become arranged in longitudinal bands which are finally prolonged up the peduncles of 

 the polyp heads. These spindles are long, either pointed at both ends or rounded off at 

 one end, seldom straight, generally sHglitly bent or /-shaped. They are very thickly 

 covered with fine, sharp spines. Their length reaches 0'6, 0-9 to 1 mm., with a thickness 

 of 0"08 to O'l mm. In the peduncle of the polyp heads they form the bundles of spicules 

 which surmount the latter ; here the spindles reach a length of 3 mm., with a diameter of 

 0"21 mm. Frequently in these spicules one end appears to be truncated and produced 

 into two short processes. The polyp heads are surrounded by eight groups of spicules 

 directed from the base to the origin of the tentacles, and projecting like teeth somewhat 

 above the latter. They are straight or slightly bent spindles and rods, covered with fine 

 spines. They measure 0-6 by 0-05 mm.; 0-58 by 0033 mm.; 0-3 by 0-025 mm.; 0-33 by 

 0033 mm.; 0-2 by 0-033 mm. 



The tentacles are folded together in repose and are covered with small red spicules. 

 The colour of the colony is various. The trunk is greyish-white, the branches and twigs 

 white. The polyp heads on many branches are dark flesh-coloured, owing to the red 

 spicules ; on others they are only yellow. 



Habitat. — Torres Strait ; depth, 8 to 1 1 fathoms. 



Station 212, off Samboangan; depth, 10 fathoms. A young colony. 



Spongodes coUaris, n. sp. 



The colony consists of an upright barren trunk and a polyp-bearing head, arranged 

 in such a manner that the stem gives off at right angles, from its upper end, up to four 

 branches, which, soon ramifying, bear umbels of polyps at their ends. 



Halfway up the trunk in young colonies, and two-thirds of the way up in an older 

 colony, there occurs a zone of flat projecting welts or folds around the stem. These 

 form a kind of collar around the stem and their margin is covered with rows of polyps. 



The trunk is fixed in the ground by means of tubular, stolon-like processes. From 

 these it rises, increasing little in size, until it divides into the aforesaid branches, 

 which come oft' from it at right angles. Up to the collar its outer covering is tough 

 and rough, in spirit but slightly folded, and even in the dry state collapsing but slightly. 

 Above the collar its consistency becomes softer ; tracts of large obliquely and trans- 

 versely placed spicules are visible to the unassisted eye, having intervening gaps of soft 



