HTMEDESMIA. 69 



spiculum only being present, tlie long, slender, 

 attenuato-spinulate. They are very minute, requiring 

 a power of about 200 linear to render their propor- 

 tions distinctly to the eye. They vary to a very 

 considerable extent in their length and diameter. 

 Two fully developed ones measured as follows : — The 

 longest was fjg inch in length and its greatest 

 diameter was stis" i^ich ; the shortest -g^ inch in length, 

 but its greatest diameter exceeded that of the longest 

 one, being 3-5^5 inch. Both these spicula were more 

 than twice the diameter of many of the other spicula 

 around them. 



" The disposition of the skeleton fasciculi is very 

 irregular, and the number of spicula contained in each 

 exceedingly variable. In some portions of the sponge 

 they consist of large flat bundles loosely congregated, 

 while in others they are much more compact, and in 

 many cases they are formed of but two or three 

 spicula; the bases and apices of the spicula forming 

 each fasciculus are almost always coincident. 



" There is no other known species of the genus 

 Hymedesmia with which this one is liable to be 

 confounded. 



"Mr. Norman states that 'this species occurs in 

 Eoundstone Bay, Galway, in small patches on the 

 under side of stones at extreme low water. Its colour 

 is a brilliant deep blue. It has long been known to 

 me by sight on other parts of the coast, and I have 

 often preserved it by drying the specimens, which 

 shrivelled up to nothing.' 



" On examining some old stores of specimens sent to 

 me in May, 1866, by my highly esteemed friend Mr. 

 C. W. Peach too late for publication in vol. ii, I found 



