o/Haliphysema Tiimanowlczli. 89 



and tliere are other specimens in close proximitj to these that 

 have the septa anastomosed, so that they do not radiate directly 

 across from centre to periphery, or from the central ring before 

 noticed, but they become divided into irregular compartments, 

 somewhat after the manner of Mr, Carter's fig. 7, pi. 4, 

 ' Annals,' 1870 (vol. v. 4th series). In many specimens the 

 radii join a central ring, which ring would appear at first, and 

 without examining a number of specimens, to be the base of 

 the pedicel ; but this is not the case, as the pedicel does not 

 go below the top of the dome-shaped test. The radii, whether 

 straight or irregular, rise from the base to the top of the inside 

 of the dome, and converge round the orifice which opens into 

 the pedicel. 



When the pedicel has been carefully removed from the top, 

 there will be seen a smooth, white, calcareous-looking ring ; it 

 has the appearance of a flat collar having been let into the top 

 of the dome. This, so far as I am aware, has not been noticed 

 before. In all the specimens of Haliphysema Tumanoxoiczii 

 that I have seen there is a rather deep depression in the top 

 of the dome-shaped test, in the centre of which the white 

 ring before mentioned is placed ; and on this ring is the base 

 of the pedicel. Taking, then, into consideration this white 

 smooth ring, it being composed of finer materials than the rest 

 of the test and of the depression in the centre of which 

 the pedicel is placed, I cannot help thinking that there are 

 provisions for a lateral movement of the pedicel when the 

 organism is alive. 



If this is a true interpretation of the uses to which these 

 peculiarities of structure are applied, I think we may claim 

 for this little sponge something more that is unique in this 

 group of organisms. 



When Dr. Bowerbank examined and described this species 

 of Haliijhysema he was not able to detect the " pores ;" and, 

 so far as I am aware, no observer has seen or described them 

 up to this time. 



On a recent examination of my specimens under peculiarly 

 good circumstances as regards light and definition, I was en- 

 abled to discover them. When the test is examined under 

 the above conditions it is seen to be composed of chitinous 

 fibres, some running parallel and others interlacing each other. 

 It is in the interstices of these fibres that I discovered the 

 pores, each pore being surrounded with minute grains of sand. 

 So far as I could see, the pores do not penetrate the entire 

 wall of the test, but only the epidermis or outer layer of the 

 chitinous fibres; they are then lost in the substance of the wall 

 of the test. 



