8§ On the "Glass-Rope" Uyalonema. 



appendage of a sponge. The discovery at Setubal proves the 

 interesting fact that a species of Uyalonema lives somewhere 

 on the Portuguese coasts or, at all events, in the course of 

 some one of the strong currents which wash, the Lusitanic 

 peninsula. The coil is hard, elastic, and insoluble — nearly 

 indestructible. I believe that during the life of the sponge 

 the Palythoa attaches itself to that portion of the coil just 

 above the sponge body, and that after the disintegration of the 

 sponge it creeps downward, naturally spreading towards that 

 end of the coil where the spicules remain in contact. 



The very fact that in all the Portuguese specimens the whole 

 of the thin end of the coil is invested by the zoophyte, would 

 suggest to me that the immediate neighbourhood of the coast 

 of Portugal may not be the habitat of the Uyalonema, but that 

 the isolated coils may have been gently drifted along the 

 surface of the mud from a distance, and during a considerable 

 space of time. 



Hyalonema seems to be generally distributed. Dr. Leidy 

 states that there is a small specimen in the museum of the 

 Academy of Sciences at Philadelphia, said to have come from 

 Santa Cruz. 



I will now describe, a little more in detail, the structure 

 and arrangement of the different parts of this singular spong-e. 

 The large silicious spicules form, as I have already mentioned, 

 a brilliant coil, in large specimens upwards of a foot and a half 

 long. The spicules on the outside of the coil stretch its entire 

 length, each taking about two and a half turns of the spiral. 

 One of these long needles is about one-third of a line in diameter 

 in the centre, gradually tapering towards either end. The 

 spirally twisted portion of the needle occupies rather more 

 than the middle half of its entire length. In the lower portion 

 of the coii, which is .imbedded in the sponge, the spicule 

 becomes straight, and tapers down to an extreme tenuity, 

 ultimately becoming so fine that it is scarcely possible to trace 

 it to its termination. Above, where the coil opens out, the 

 spicule likewise becomes straight and tapers, but in all 

 the specimens which have been examined the upper ends of 

 the spicules have been broken off. The surface of the middle 

 and lower portions of the spicule is perfectly smooth, but the 

 upper part, where the coil is frayed out, has a frosted Jook, 

 and feels rough to a finger drawn along it upwards. This 

 roughness depends upon a scries of little crest-like elevations, 

 armed with minute teeth, which stretch about half way round 

 the needle on alternate sides, at short intervals ; or sometimes 

 two of the crests unite into an irregular spiral ridge (Plate, 

 Fig. 1). 



Under the microscope, by transmitted light, the spiculum 



