24G CEYLON PEARL OYSTER REPORT. 



Fig. 7. Auhtta elmgata; R.N. 73. Spicules, x 79. a, b, styli; c, oxeote; <7, e,/, strongyla. 

 8. Lewosolenia cmiacea, var. ceylonensis; R.N. 37 7. Spicules, x 360. 



a, A, i , triradiates ; d, portion of oxeote. 

 it. Leucosolenia temipilosa ; R.N. 158. Spicules, x 360. <i, triradiate ; b, quadriradiate, facial view ; 

 c, quadriradiate, side view, showing apical ray ; d, part of oxeote. 

 , 10. Leucanclra donnani ; R.N. 186. Spicules, x 79. 



a, b, parenchymal triradiates; c, d, dermal triradiates; e,f, gastral quadriradiates ; g, oxeote. 



PLATE XIV. (All the figures from photographs.) 



Hircinia fusca ; part of R.N. 48, x f. 



Hippospongia clathrata ; R.N. 24, x }i. 



Euspongia officinalis, var. ceylonensis ; R.N. 37a, x about |. 



Spongelia elastica, var. crassa; R.N. 35, x about f. 



Hircinia anomala ; R.N. 1 3, x about S. 



Phyllospongia papyracea, var. ; R.N. 104a, x \i. 



Megalopastas nigra ; R.N. 71, x . 



PLATE XV. 



Fig. 1. Iiiuviiirlhi simplex ; R.N. 302. End of primary fibre, enclosed in conulus, x 230. 



2. Darwinella simplex ; R.N. 302. Portion of primary fibre, in which the pith (p.) is partially replaced 

 by fungal (?) filaments (/.), x 230. 



3. Megalopastas pidvilhs; R.N. 191. Portion of skeleton as seen in vertical section, showing the old 

 apices of primary fibres (ap.) enclosed in younger portions of the fibres, x 79. 



4. Diagrammatic sketch of the general anatomy of the genus Megalopastas, based upon vertical 

 sections of a specimen of M. elegans (= Dendrilla elegans, Lendenfeld) from Port Phillip 

 Heads, Australia, x 52. r., surface conuli ; ex., embryo capsules ; cm., embryo; ex.e., exhalant 

 canals; f.c, flagellate chambers; i.e., inhalant canal; p.f., primary skeleton fibres; p.s., pore- 

 sieves; s.c., subdermal cavities; s.f., secondary skeleton fibres. 



,, 5. Megalopastas nigra; R.N. 161a. Part of skeleton, as seen in vertical section, including the dermal 

 skeleton (d.-g.) as well as the main skeleton, x 52. 



6. Megalopastas nigra; R.N. 161 A. Dermal skeleton, x 52. 



,, 7. Megalopastas nigra ; R.N. 161a. 



End of primary fibre, showing mode of growth and origin of secondary fibres, x 230. 



8. Megalopastas nigra ; R.N. 161a. 



Origin of new primary fibre from a secondary fibre of the dermal skeleton, vertical section, 

 x 230. c, surface conulus; d.s., dermal skeleton; p.f., new primary fibre. 



PLATE XVI. 



Fig. 1. Hircinia anomala; R.N. 82. Part of skeleton, as seen in transverse section, x 52. 

 2. Hircinia tuberosa; R.N. 88a. Part of skeleton, as seen in vertical section through the surface, 



including the sand-cortex (s.c), x 52. 

 ,, 3. Hircinia schulzei; R.N. 277. Part of skeleton, as seen in vertical longitudinal section, x 52. 

 4. Aplysina herdmani ; R.N. 340. Part of skeleton, as seen in vertical section of body, x 79. 

 5. Euspongia officinalis, var. ceylonensis; R.N. 101. Part of skeleton, as seen in vertical section, x 79. 



