142 



The whole colony is very rigid, but in spite of this there has evidently been 

 a collapse of the body waWs consequent on death. The armature both in the 

 general colony and on the calyces is very dense. In the main stem the canal 



walls are packed with large spindles longitu- 

 dinally disposed. On the outer surface the 

 longitudinal arrangement of the interlocking 

 spindles is very evident to the naked eye, even 

 forming in some places distinct ridges. 



The polyps arise either singly or in groups 

 of two to ten, both on the primary branches and 

 on the secondary lobes, but are more clustered 

 on the latter. Above the origin of the primary 

 branches, a few scattered polyps occur on the 

 main stem. The polyps are borne on distinct 

 stalks which are supported by very large spicules 

 standing out in relief from the general coenen- 

 chyma. These stalks sometimes attain a length 

 of 2'5 mm. and occasionally one or two of the 

 spicules project beyond the origin of the polyp 

 so as to suggest the appearance of a "Stutz- 

 blindel ". The spicules of the stalk are very irregularly arranged and curve 

 to the contour of the lobes. The polyps arise at an obtuse angle to the stalk 

 and are supported by eight indefinite groups of spicules, so arranged as to give 

 a slight indication of eight triangles. There is a double row of spicules on 

 the aboral surface of the tentacles and these form a pseudo-operculum over 

 the retracted polyp. 



The colour is dull brown but the stem is distinctly paler ; the small colonies 

 are yellowish-brown. 



This sjjecies comes near Stereamnthia indica, Thomson and Henderson, but 

 is easily distinguished from it by the denseness of the armature and by the 

 large size of the spicules. 



The following are some of the measurements in millimetres : — 



(a) Stem : large warty spindles, 5 x 0'68 ; 1'6 x O'S. 

 (//) Twig : large warty spindles, 2 x 0'45 ; 1'3 x 0'3. 

 Spiny spindles — more slender, 1"2 x 012 ; 1'8 x OH. 



Locality : Andamans. 



Fig. 69. Stereacanthia armata, n. sp 

 — Terminal portion of twig, x 2. 



