1114 A MONOGaAPH OP THE AUSTRALIAN SPONGES, 



Dermal triradiate spicules. Like the quadriracUates just described, 

 regular, but more constant with respect to the proportion of the 

 length of their rays to their thickness ; this proportion varies from 

 10/1 to 16/1. Kays smooth, of conical or cylindrical form, bluntly 

 pointed, average length 0-6 mm. 



Locality: Station 163a, 1874; off Port Jackson, Australia; 

 depth, 30 to 35 fathoms, rock. Challenger. 



29. SPECIES. VOSMAERIA HAECKELIANA. Von Lendenfeld. 

 LEUCETTA HAECKELIANA. N.PoMjaeff (1). 



The largest specimen reaches 65 mm., in length with a maximum 

 diameter of 10. ; the walls are 2*5 mm., thick, the cortex strongly 

 developed. The outer surface is smooth, the inner slightly rough. 

 Gastric and parenchymal quadriradiate spicules : either regular or 

 sagittal, the lateral rays becoming more or less curved, or even 

 irregular, all rays instead of being straight becoming irregularly 

 bent and of different lengths ; all rays of the same average diameter 

 0'005 mm., tapering from base to sharp points; facial rays 0*02 

 mm., to 0-08 mm. The gastric radiate spicules follow the course 

 of the exhalent canals throughout their whole length, and their 

 presence or absence on the surface of the cavities of the parenchyma 

 intimates whether we have to do with an exhalent or inhalent canal. 



Dermal quadriradiate spicules : Extraordinarily rare ; regular ; 

 all rays of the same length not exceeding 0*75 mm., by 0-075 mm., 

 smooth tapering from the base to sharp points. 



Dermal triradiate spicides : Regular, rays of a rather cylindrical 

 form, 0-55 mm., long, 0-03 ram., in diameter, lying in the cortex 

 in several parallel layers, becoming smaller in the low collar and 

 sagittally differentiated, the angles between basal and lateral rays 

 becoming more acute, 120°-95°, and the lateral rays themseh^es, 

 like those in the Oscular triradiate spicules of Leucetta vera 

 becoming horn-shaped. 



Locality: Station 163a, June 3, 1874, off" Port Jackson, 

 Australia ; depth, 30 to 35 fathoms, rock. Challenger. 



(1.) N. PoUjaeff. L.c, p, 69, PI. II., fig. 6 ; PL VIII., figs. 1-6. 



