EIPLANATIOW OF THE PLATES. 677 



Pig. i. SteUeita clavosa, aeerate, anctoring quadriradiate, and zone 

 spicules, X 68. i', head of zone-'spioule, as seen from 

 above, x 68 ; i", stellate flesH-spieiiles, x 370. From type 

 specimen from Prince of Wales Channel. 



j. S. purpurea, aeerate, anchoring quadriradiate, and zone- 

 spicules, X 68. /, stellate flesh-spicules, x 370. From 

 type specimen from Torres Straits. 



h. S. purpurea, var. retrofiexa, the zone-spicule, X 68. From 

 specimen from Torres Straits. 



I. Tethyopsis dissimilis, diagrammatic vertical section* across 

 upper end of larger f specimen from Port Dar;m;n, x about 

 2. Z'. The same* of smaller specimen from Port Darwin, 

 X about 3 [the dark parts represent canals, the dotted 

 portions those occupied by the skeleton and tissues in the 

 Sponge itself]. I". Portion of dermis % from between two 

 longitudinal skeletal lines, from larger specimen from 

 Port Darwin, as Seen from inside, x about 25. V". Part 

 of septum^ between two large canals, from same specimen, 

 X about 25. I"". Skeleton triradiate spicules, one normal, 

 the other with abnormally elongated third ray, x 34. 

 J!"". Aeerate spicule from small Port-Darwin specimen, 

 and Z""", from Torres-Straits specimen, x34. Z'""". Flesh- 

 spicules from larger specimen from Port Darwin, x 850. 



m. Leucaltis lathybia, var. australiensis, tri- and quadri- 

 radiate spicules of outer surface ; m', triradiate from 

 , centre of wall ; m!', quadriradiates of subjacent parts. All 

 X 68. From type specimen from Port Jackson. 



n, Stellettinopsis carteri, the skeleton-spicule, X 68. n', the 

 larger, and n", the smaller stellates, X 370, From type 

 specimen from Torres Straits. 



* Canals. — 1, anterior ; 2, posterior ; 3 and 4, lateral ; 5 and 6, antero- 

 lateral ; 7 and 8, post.ero-lateral ; 9 (in l), axial. 



t Note. — Since writing the account of the canals (given at p. 478 of Part I. 

 of the Report), I have discoyered that the apparently single pair of lateral spaces 

 in the larger specirhen is in reality double. 



I Showing that the long arm of the skeleton-spicule commonly extends over 

 two interfascicular spaces, and is not confined to one as stated in the description 

 at p. 477. 



