198 CEYLON PEARL OYSTER REPORT. 



in Liverpool) shows none of the very large spicules characteristic of the variety 

 manaarensis previously described hy me (3), though it is not impossible that such 

 may occur in other parts of the sponge. 

 R.N. 29 (Gulf of Manaar). 



Ciocalypta tyleri, var. aberrans, nov. 



The single specimen consists of a flattened, cushion-shaped body of oval outline, 

 with ^ number (now four, but apparently one at least has been broken off) of slender, 

 upright, digitiform processes springing from the upper surface. These processes are 

 long and conical, tapering gradually almost to a point, and with no visible vents ; 

 their walls, however, are pierced by numerous small dermal pores. The surface of 

 the sponge between the roots of the processes is rather uneven and somewhat rugose, 

 with branching canals radiating from the roots of the processes beneath the surface, 

 through which they are plainly visible ; these canals are continuous with the large 

 canals which run lengthwise through the digitiform processes, about four in each. 

 The general surface of the sponge is very minutely hispid ; the walls of the 

 processes have a minutely reticulate appearance and may also be very slightly hispid. 

 The texture of the basal part of the sponge (which has been cut off below) is fairly 

 compact, except for the numerous cylindrical canals, some of which run almost 

 vertically downwards from the bases of the digitiform processes. The colour of the 

 sponge (in spirit) is dull brownish-grey. The longer diameter of the base measures 

 about 45 millims., the shorter diameter about 24 millims. ; the thickness in the middle 

 of the base (now) is about 13 millims. The digitiform processes are about 29 millims. 

 long and 6 millims. in diameter at the base, from which they taper gradually to the 

 narrow, blunt apex. 



The skeleton in the body of the sponge is a dense, irregular reticulation of loosely 

 scattered spicules, chiefly oxeote, of various sizes. There is no special dermal skeleton 

 and no extensive sub-dermal cavities, and the spicules at the surface do not differ in 

 size, form, or arrangement, from those below. In the digitiform processes there is a 

 central axis surrounded by about four longitudinal canals, separated from one another 

 by rather thin longitudinal septa radiating from the central axis. Both axis and 

 septa are crowded with spicules similar to those in the body of the sponge, but mostly 

 arranged lengthwise. From the more peripheral portions of the septa radiate loose 

 brushes of, for the most part, more slender and shorter oxea, which spread out beneath 

 the dermal membrane and support it on their apices, which may project slightly 

 beyond the surface. Although the more peripherally placed spicules of each brush 

 are inclined very obliquely to the surface, there is no true dermal reticulation, but the 

 dermal membrane may contain irregularly scattered spicules of various sizes. 



Spicules. Oxea of various dimensions ; usually gently curved, symmetrical, 

 gradually and fairly sharply pointed at each end ; sometimes biangulate instead of 

 simply curved ; occasionally stylote with broadly rounded base. Size varying up to 



