882 DR. J. STUART THOMSON ON 



intei'val of 12 mm. This second branch measures 11 mm. in 

 lengtli and 3 mm. in diameter. 



The main shoot is 21 mm. in height and has a diameter of 

 5-6 mm. at the apex. 



The surface of the ccenenchyma is covered with large, yellow 

 spicules, which are easily seen with the naked eye. They lie ad- 

 jacent to one another but do not overlap, the boundaries of each 

 being clearly defined. These superficial spicules of the ccenen- 

 chyma do not appear to be arranged in any very definite manner 

 in relation to one another ; they are of such varied sizes that any 

 great regularity is prevented. It may, however, be observed that 

 all the superficial spicules of the ccenenchyma have their long axes 

 in the direction of the longitudinal axis of the colony; in the 

 verrucee, the spicules have a cori-esponding position in relation to 

 the polyps. 



The spicules of the cortex are (1) broad spindles, yellow in 

 colour, (2) long narrow spindles, of a pale colour. The spicules 

 project very much on the surface at all parts. The spicules of 

 the anthocodise are red and are long spindles arranged * en chev- 

 ron ' in eight longitudinal, triangular areas. At the base of these 

 strips, a layer of spicules forms a ring round the polyp. This ring 

 is composed of two or three spicules lying one behind the other iia 

 a proximo-distal direction. 



The verrucpe have a circle of projecting spicules, only one layer 

 deep. This circle consists of 14-16 yellow spicules which lie with 

 their long axes pai-allel to the length of the polyps. These pro- 

 jecting spicules appear to be more prominent towards the apex of 

 the colony. The general appearance of the polyp spicules reminds 

 one, at first sight, of the setting of a stone in a finger-ring ; the 

 anthocodia with its red spicules resembling a jewel which is 

 surrounded by little rivets, namely, the large, yellow spicules of 

 the verrucfB. The degree to which the anthocodipe are exposed 

 beyond the verrucse varies to some extent ; as a rule, eight trian- 

 gular areas are easily seen, in other cases there is only a minute 

 area with spicules or only an opening at the apex of the verrucpe. 

 The axis is horny in the centre, but with long nai"row needles or 

 spindles on its surface. These axial spicules are about 0*340 mm. 

 in length and 0*051 in breadth ; their margins are almost smooth. 

 In a rough transverse section, the axis is seen to be composed of 

 a lai-ge central grey area surrounded by a brown ring. The axis 

 is not penetrated by canals. 



The polyps occur on all parts of the colony including the basal 

 encrusting part ; they are arranged in a spiral manner on the 

 branches. The polyps are about 1*5 mm. in height and 2 mm. in 

 diameter. 



The dimensions of the spicules are : — (1 ) large, yellow spindles, 

 from 0-081 x 0*039 to 0*123 x 0*021 mm.; (2) small, yellow 

 spindles, from 0*042 x 0*024 to 0*093 x 0*033 mm. ; (3) red spindles, 

 from 0*021x0*0015 to 0*114x0*0135 mm.; (4) long needle-like 

 spicules of the axis, 0*340 mm. in length by 0*051 mm. in bi-eadth. 



