674 EXPLANATION OF THE PLATES. 



Fig. z. Oellius cymiformis. Spicules, x 370. From specimen from 

 Thursday Island. 



aa. Crella schmidti. Spicules (anchorate from front and side), 

 X 370. From type specimen from Port Jackson. 



bb. GeUiodes fibulata, fibre of part of vertical section, showing 

 the very stout and straight primary and the secondary 

 fibres ; bb', portion of secondary fibre, showing arrange- 

 ment of spicules and isolated skcleton-spicule : x 68. 

 bb". Bihamatc spicules, x 370. From dry specimen from 

 Prince of Wales Channel. 



cc. Amphilectus tibiellifer, skeleton acuate and tibiella-spicules, 

 X 190 (head of latter enlarged), cc'. Tricurvate acerate, 

 X 190. cc". Anchorate seen from front and side, x 370. 

 From one of the types from Prince of Wales Channel. 



Plate XLII. 

 Fig. a. Myxilla arborescens, portion of vertical section, x 190. 

 a'. Skeleton acerate spicules, x 190. a". Equianchorate 

 spicule from front and side, x 370. From type specimen 

 (in spirit) from Port Jackson. 



b. Acamus ternatus, acnate, grapnel, and tricurvate spicules, 



and head of grapnel as seen from above, x 190. b'. Ti- 

 biella and equianchorate (from front and side) spicules, 

 X 370. From specimen from West Island, Torres Straits. 



c. Ophlitispongia australiensis, fibre of vertical section, x 190. 



c' . Skeleton cylindrical and echinating acuate spicules, 

 X 190. From type specimen from Port Molle. 



d. Clathria tuberosa, vertical section, x 38. From specimen 



in spirit from Prince of Wales Channel. 



e. lotrochota purpurea, vertical section, and e', dermis, x 



20. e". Two sizes of skeleton-spicule, x 190. e'". Biro- 

 tulate spicules, x 370. From dry specimen from Prince 

 of Wales Channel, e"". Two ciliated chambers, from 

 specimen of green var. from Amirante Island, x 370. 



/. /. baadifera, tibiclla-spicule of dermis, x 370. From 

 type specimen from Port Darwin. 



