92 On the "Glass-Rope" Hyalonema. 



2, the form with produced polyps, investing the same species, 

 and distinguishing Hyalochceta Possieti of Brandt; and, 3, 

 the species with oval polyps more regularly arranged, which 

 seems to be constantly associated with Hyalonema Lusitani- 

 cum. 



Such is an outline of the structure of Hyalonema, so far as 

 it can be made out from dried specimens. After the careful 

 microscopic observations of Schultze, I think there can be no 

 doubt whatever that the silicious coil and the sponge form one 

 organism. Perhaps the most conclusive proof of this is the 

 essential correspondence in structure and plan of growth 

 between the long spicules of the coil and the spicules of the 

 body of the sponge ; and the peculiarity of that mode of 

 growth distinguishes Hyalonema from most other sponges. 

 Since Professor Schultze' s memoir was written, many additional 

 specimens have been brought to Europe. All of these, so far 

 as I know, are in the same dried and partially mutilated 

 state. I saw, I should think, nearly a hundred in London last 

 year. Most of them had lost all traces of the sponge, and 

 almost all were coated through the greater part of their length 

 with Palythoa. The zoophyte was often continued quite 

 down to the lower end of the coil, which in all these cases was 

 more or less truncated and injured. Many of the specimens 

 had the egg-bags of a small shark or dog-fish attached to 

 them. From the appearance of all I have little doubt that the 

 coils had first of all got disengaged from their investing 

 sponges by the decay of the sponges or by a storm, and that 

 afterwards the Palythoa, and other animals and plants, attached 

 themselves to the free coils lying between the rock-pools or 

 between tide-marks. 



The two specimens figured in the woodcuts are among those 

 in the Museum of Queen's College, Belfast. In one of these 

 (Fig. 1) the thin end of the coil is entirely coated with the 

 incrusting zoophyte. The polyps stand out considerably from 

 the general surface of the crust, and here and there the 

 caenosarc and the polyps run together into irregular, projecting, 

 knob -like masses. This specimen must clearly be referred to 

 the form named by Brandt Hyalochceta Possieti, indeed, it 

 closely resembles the specimen from which Brandt's figure was 

 taken. One of the terminal polyps has been broken off', and' the 

 truncated, somewhat worn end of the coil has been thus 

 exposed. As the thin end of the coil is always uncovered by 

 the zoophyte when it is inserted into and connected with the 

 sponge, and as the coil could not possibly have been poised in 

 the sponge without any attachment/ and in its present 

 condition, it is evident that in this case the " polypigerous 

 crust" must have been extended over the end of the coil after 



