552 A MONOGRAPH OF THE AUSTRALIAN SPONGES. 



Plate 37. 



Fig 1. — Euspongia canaliculata. 11. v. L. Var. daatica. 



Transverse section through the outer portion of one of the digitate 

 processes. 



Combined picture. 



450:1 magnified. 



{P) Pore-sieve, (p) Inhalent pores. (a) Askeletous portion of tlie 

 sponge, (.s) Slieletous portion cf the sponge. {M) TJadiating 

 main fibre charged witli sand, etc. {S) External sand armour 

 in the outer skin in direct connection with the sandy core of 

 the main fibre. ( V) Connecting fibres free from foreign bodies. 

 (6) Sharp pointed ends of the connecting fibres at the limit of 

 the skeletous portion of the sponge {c) Axial thread in the 

 connecting filjres. (0) Ci roups of ova. (E) Endothel cell- 

 capsules, including the ova-groups, {d) .Sub-dermal cavities 

 belonging to the inhalent system, (e) Inhalent canals, (f) 

 Exhalent canals, (i) Lacuna; of the exhalent system in the 

 askeletous portion of the sponge. {G) Ciliated chambers, 

 (/i) Muscular membrane dividing the skeletous from the 

 askeletous portion of tlae sponge, consisting of highly granular 

 spindle-shaped cells. (*) Ganglion on the distal end of tlie 

 muscular membrane, {k) Tangental nerves issued from tlie 

 ganglion. [1] Sensitive cells in connection with the ganglion. 



Plate 38. 



Fig. 1. — Euspongia sUicata. R. v. L. 



Transverse section through the outer portion of the sponge. 

 Alcohol, Alum-carmin. 

 100:1 magnified. 



(a) Primary inlialent canals, {h) Sub-dermal cavities, (c) Conuli. 

 (m) Main fibres. 



Fig. 2. — Euspontjla silicata. R. v. L. 



Transverse section through the outer skin. 



Alocohol Alum-carmin. 



1000:1 magnified. 



(d) gland cells, [h) Inhalent pores, (c) Narrow, primary, inhalent 

 canals leading from the pores into the sub-dermal cavity, {d) 

 Sensitive cells. (The hypothetical palpocils (<?) are not visible 

 in the sections.) (f) Flat ectodermal cells. [g) Muscular and 

 connective cells, spindle-shaped or multiplolar. (h) Amaboid 

 wandering cells. 



