370 SYDNEY J. HICKSON. 



lancet- or spindle-shaped, and others again slightly curved like 

 a boomerang. These long unbranched spicules occur chiefly in 

 the tentacles and disc of the polyps. They do occur in other 

 parts of the colony, but I do not remember to have seen any 

 dumb-bell-shaped spicules in the extensible portion of the 

 polyps. 



When one examines a similar preparation of the spicules of 

 the yellow variety of Alcyonium digitatum, one notices 

 precisely the same forms in very much the same proportions. 

 In fact, if it were not for the faint yellow colour which they 

 all possess, it would be impossible to distinguish them from the 

 spicules of the white variety (fig. 4). 



The figures were drawn by Mr. Wilson, from preparations 

 in my collection of the spicules of the yellow (fig. 4) and white 

 (fig. 3) variety respectively ; the specimens were selected by 

 him quite at random from a very large number on each slide. 



A preparation of the spicules of the other English species, 

 Alcyonium glomeratum, presents many features of 

 marked difference from those of the yellow and white varieties 

 of A. digitatum. In the first place, the colour is of various 

 shades from pale pink to blood-red. The majority of the 

 spicules are elongated needles and spindles, and there is an 

 entire absence of the small dumb-bell-shaped forms, very few 

 K^s and crosses, and there are several club-shaped forms 

 (fig. 5), which I have never seen in any preparations of 

 A. digitatum. 



While, then, I have found it impossible to distinguish the 

 preparations of the spicules of the varieties of A. digitatum 

 by any other characters than the colour, a preparation of the 

 spicules of A. glomeratum can be easily and immediately 

 I'ecognised by the numerous characters given above. It is 

 true that many of the elongated and spindle-shaped spicules of 

 A. glomeratum are almost exactly the same shape as the 

 spicules of the tentacles and disc of the polyps of A. digi- 

 tatum, but the clubs are peculiar to it, the dumb-bell absent, 

 and the K^s and crosses very rare. 



Alcyonium digitatum is not a favorable form to take 



