254 



and disposed longitudinally. They are not iinifoi'm in size, but there does not 

 seem to be any definite mode of arrangement among the larger forms ; in some 

 cases these extend from the base of one verruca to that of the next, but often 

 they lie encircling the base of the verrucas. On the main stem and larger 

 branches the longitudinal arrangement is by no means obvious ; there are 

 fewer large spicules and these often lie almost transversely. This feature is 

 very important, especially in the identification of a species from a detached 

 fragment. 



There is a marked flattening of the stem and branches in the plane of 

 ramification, but in the younger twigs this often entirely disappears. The axis 

 is horny and slightly fiexible ; it is brown in colour at the base but yellow in 

 the twigs. 



The disposition of the verrucre is also a character which shows considerable 

 variation. In one specimen the main stem and larger branches are quite devoid 

 of jjolyps, while in another the surface is irregularly covered with them. On 

 the secondary branches verrucce occur almost all round, but on the twigs they 

 are crowded on the sides and are sub-alternate ; younger forms arise between 

 them and break the otherwise regular contom-. The verrucse are small trun- 

 cated cones about 0'5 mm. in height and 075 mm. in diameter at the base, 

 but when fully retracted they are dome-like ; those on the main stem and 

 larger branches are smaller and wart-like. The spicules are smaller than those 

 of the ca'nenchyma and are arranged longitudinally ; in some places they are 

 grouped in eight bundles with eight projecting points. The base of the verruca 

 is embedded in the ccenenchyma. 



The tentacular operculum is only feebly developed ; the collaret consists 

 of two or three rows of slightly interlocking, curved spindles, and standing upon 

 this are the eight points, each formed of about four curved spindles arranged 

 " en chevron," but in some cases six or seven are present with no definite 

 arrangement. 



The spicules are warty and spiny spindles, straight, curved, or slightly S- 

 shaped, pale red or orange in colour ; those of the operculum are colourless and 

 much smaller. The following are some of the measurements length and breadth 

 in millimetres : — 



{«) Ccenenchyma of main stem, U45 x 0-05 ; 0-25 x 0-025 ; 0-2 x O'OS. 



(Ij) Ccenenchyma of twigs, 0-8 x Ol ; 07 x 0-075 ; 0-5 x 0-06 ; 0-2 x 0-05. 



(r) Verrucffi, 0-45 x 0-05 ; 0-4 x 0-045. 



(d) Tentacular operculum, 0-2 x 0-03 ; 0-175 x 0-025. 



Localities : Andamans, 270-45 fathoms ; off Ganjam Coast, 18 fathoms. 



Previously recorded from the Ceylon Seas. 



