94 On the " Glass-Rope" Ilyalonema. 



sponge in its fresh state, and it is very unlikely that where 

 the bark was so thoroughly removed, the sponge should have 

 been saved. In the other specimen the sponge was wanting, 

 but the lower part of the rope was well coated with Palythoa. 

 Into and through its crust were twined and twisted the 

 suspending cords of the egg of a dog-fish, and in several 

 places the indiscriminating zoophyte had erred from the 

 glassy coil, and coated with a uniform and impartial layer, 

 the cords of the dog-fish's egg ! 



The glassy whisp of Hijalonema is certainly very remark- 

 able, but it is not entirely without analogy. Hijalonema seems 

 to represent the extreme form of a little group of sponges, 

 including, with probably a few other known forms, Hupledella 

 (Alcyoncellum) speciosa (Quoi and Gaimard), and E. cucumer 

 (Owen) . The latter of these is an oval sponge, with silicious 

 spicules whose form is somewhat analogous to that of the 

 spicules of Hijalonema. From one end of the sponge a tuft of 

 long silicious threads, resembling in structure those of the 

 Japan sponge, twdne round a stone, or other foreign body. 

 Dr. Bowerbank isolated one of these spines of Eupleciella, three 

 inches long. 



DESCEIPTION OF THE PLATE. 



Fig. 1. Hijalonema Sieboldi (Gray), from a specimen in 

 the British Museum. 



Fig. 9, fragment of the upper part . of one of the large 

 needles of the coil ; Figs. 2— 8, 10, various forms of spicules. 



