16 LEUCANDRA. 



Leucandra saccharata, Haeckel. 



Leucandra saccharata, E. Haeckel, Die Kalkschwiimme ; eine Monographie, 



Band ii. Seite 228 (1872). 

 Leucandra saccJiarata, E.. von Lendenfeld, Das Nervensystem der Spongien, 



Zoologischer Anzeiger, viii. Jahr. no. 186 (1885), 

 Leucandra saccharata, R. von Lendenfeld, " A Monograph of the Australian 



Sponges. — Part III.," Proceedings of the Linnean Society of New South 



Wales, vol. ix. part 4, p. 1137 (1885). 

 Leuconia saccharata, S. O. Ridley, Report on the Sponges, Report on the 



Zoological Collection made in the Indo-Pacific Ocean during the Voyage 



of H.M.S. 'Alert,' 1881-82, p. 482 (London, 1884). 



This sponge occurs in the shape of solitary persons, and also in colonial 

 forms, with or without oscula. The solitary form, with a naked osculum, has 

 the shape of a cylinder or cone, and is sometimes compressed leaf-shaped 

 measuring 10-50x5-30 millim. It is attached by a broad base, or a rudi- 

 mentary solid peduncle. The osculum at the terminal end is circular or oval, 

 and measures 3-10 millim. in diameter ; sometimes it is closed. The colonial 

 forms appear as large undulating masses with highly projecting gyri, often 

 similar to a " range of volcanoes " (Eaechel, I. c). The largest sponge seen by 

 Haeckel measured 60 x 40 millim. Carter was therefore wrong in saying that 

 his Teichonella prolifera is " by far the largest calcisponge on I'ecord." I have 

 seen specimens measuring 140 x 80 x 30 millim., which were only fragments 

 brought up by the dredge ; so that although the upper limit of size to which 

 this sponge may grow is unknown, it is clear that this species is a giant among 

 the Calcarea. 



The body-wall is from 2 to 5 millim. thick ; the gastral cavity follows 

 in shape the outer surface pretty regularly, but is not influenced by the 

 external gyri. The canal-system appears simple ; the outer cortex is perforated 

 by numerous small pores, which are equidistant, and which measure 0*04 millim. 

 in diameter ; the solid parts of the cortex between them are of the same dimen- 

 sions as the pores. Below the pores the inhalant canals commence with trumpet- 

 shaped extensions, and lead centripetally downwards into the parenchyma. 

 These canals are cylindrical, and situated radially ; they measure 0*16 millim. 

 in diameter, and do not taper towards their centripetal termination, but end 

 cid-cle-sac-\ike. No tangential inhalant canals are met with : there exist no 

 anastomoses or subdermal cavities ; the ciliated chambers measure 0*04 millim. 

 in width. The exhalant canal-system is slightly more complicated. Radial 

 canals, parallel to the inhalant ones, lie between the latter, and have the same 

 shape and dimensions as these. They do not open directly into the gastral 

 cavity, but join it by means of short tangential tubes ; 5 to 20 of these 

 coalesce to a very short radial tube 0*1 millim. in diameter, which opens into 

 the gastral cavity with a trumpet-shaped extension. 



