SPONGES— II ALLM ANN. 



133 



maximiiDi diameter of 18 yi. Microsderes : — {i.) Mi- 

 croxea, 100 to 140 ji in lem^^th hy about 4 }i in diameter; 

 {ii.) ampliiasters, 4 to 5 ;: long. 



The single specimen is a moderately 

 large, massive, sessile sponge, of great 

 density and solidity, with a rounded 

 CLiboidal or sub-globose body which 

 measures about 120 mm. in each of its 

 three principal directions. From the 

 marginal region of the somewhat flat- 

 tened upper surface of the main body 

 there are given off, at sub-equal dis- 

 tances, three stout branch-like pro- 

 cesses, 100 to 150 mm. in length. One 

 of these is cylindrical, the others are 

 club-shaped and are polytomoush- 

 di\ ided at their extremities into in- 

 cipient branches. The specimen, which 

 has been longitudinally bisected, is, with 

 the exception of one of its processes, 

 preserved in a dry state. The contrac- 

 tion resulting from drying has caused 

 the surface to split in places, giving rise 

 to a number of shallow gaping fissures, 

 such as are occasioned under similar 

 circumstances in many Axinellids. The 

 surface of the dried portion somewhat 



resembles short-piled velvet, both in 



appearance and to the touch ; that of 



the spirit piece has a harsher feeling. 

 The colour of the former is yellowish- 

 white, both externally and internally ; 



the latter is similarly tinted, except 



superficially, where to a depth of about 



one-third of a millimetre, it exhibits an 



intense purple colouration which, how- 

 ever, is almost certainly a stain derived 



from crinoids originallv preser\ed in the 



same liquid. The texture, as revealed 



by the cut surface resulting from the 



bisection of the specimen, bears a close 



resemblance to that of some coarse and 



exceedingly short-grained hardwood. 



The denselv packed spicules are visible ^^ that of the other 



to the naked eve, and throughout the frt^"^" 1 I ^\^\ *°^ 

 ^ , - ^ , ^ ^ the dermal brushes), c 



entire central mass of the sponge have Microxea. 



Fig. 26 — P. li^nea. 

 a Oxea (showing the 

 spicule's extremities, and 

 its diameter relatively 



