128 Mr. H. J. Carter on 



the Jine spicules; no. 2 equally present in the wall-structure 

 and its outer and inner layers, viz. that of the surface and that 

 of the cloaca respectively ; no. 3 is chiefly confined to the 

 cloaca, where its fourth ray, which is short and curved, 

 thickly echinates not only the general surface of this cavity, 

 but the circular margins of the holes and the surface of the 

 canals within them respectively. Size of specimen 3^ inches 

 long by 10-12ths inch in its widest diameter. 



Obs. One cannot help seeing in this specimen the Austra- 

 lian representative of the British Leuconia Jistulosa, Bk.,= 

 Grantia Jistidosa, Johnston, of which the type specimen is 

 in the British Museum ; nor can we help seeing in the excre- 

 tory canal-system a close approach to that of the non- 

 calcareous sponges. 



29. Leuconia hispida. 



Individualized. Erect^ conoglobular, compressed, con- 

 tracted towards the base, peristomed. Colour whitish yellow 

 on the outside, sponge-brown within. Surface thickly echi- 

 nated with comparatively thin fusiform acerates, held together 

 rather confusedly in indistinct groups by cribriform sarcode, 

 which in the intervals often presents defined areas. Pores, 

 viz. the holes of the cribriform sarcode, of different sizes, 

 varying under 1-45 1st in. in diameter. Vent single, circular, 

 terminal, on the summit, provided with a peristome about 

 l-16th in. in diameter, leading into the cloacal cavity, which 

 becomes three times as wide, corresponding in form with that 

 of the specimen ; holes in the cloaca very variable in size and 

 distance apart, the latter depending on the width of the cloaca- 

 skeletal structure between them ; presenting within their 

 border from one to four or more circular openings, which 

 belong to the excretory canals of the internal structure ; 

 thus every hole in the cloacal surface is tantamount to that 

 of a subcloacal vent ; surface of the cloaca and margins of the 

 holes respectively thickly echinated with the long curved 

 fourth arms of quadriradiates. Structure of the wall, which 

 is thick, cancellated, traversed by the canals of the excretory 

 system, supported skeletally on smallish triradiates. Spicules 

 of three kinds, viz. acerate, triradiate, and quadriradiate : — 

 1, acerates, of two forms, viz. one long, thin, straight, cylin- 

 drical, silky, and the other slightly curved, stouter, and fusi- 

 form, the latter averaging 200 by 4-6000ths in. ; 2, triradiates, 

 all apparently about the same size, which is comparatively 

 small, regular and irregular, with the arms in different degrees 

 of sagittal expansion ; 3, quadriradiates, numerous. No. 1, 



