306 



The polyps diminish in number towards the Imse of the trunk. 



The spicules are very characteristic and mark this species as distinct from 

 C. liithenii, to which it is most closely allied. All are smooth and hyaline and 

 many show very clearly the lines of growth (see fig.). The following are some 

 of the types with measurements in millimetres : — 



(A) Trunk :— 



{n) Cylindrical forms, 0-2 x 0-03 ; 0-125 x 002. 



{h) Cylindrical with epiphysis-Hke terminations, 0-225 x 0-03 ; 0-2 x 0-02. 



(<■•) Cylindrical with broad bifurcations at one end, some of which are 



almost T-shaped, 035 x 0-08 ; 03 x 006 ; 0225 x 0035. 

 {(1) Cylindrical with knob at one end and bifurcation at the other, 



0-35 X 0-075 ; 03 x 006 ; 025 x 0055. 

 {(') Bifurcated at both ends, the smaller forms resembling vertebrae, 



0-4 X 0-1 ; 0-35 x 0075 ; 0-2 x 004. 

 (/) Flattened forms with rings of growth like the shell of Solen, 03 x 0-025 ; 



0-25 X 0-02. 

 There are numerous irregular and intermediate types ; in some the bifurca- 

 tions are smooth, in others they are again sub-divided. 



(B) Stalk :— 



[a) Short spindles with rather rounded ends, 0-1 x 0-02 ; 0-075 x 0-02. 



{b) Spindle-shaped, broader at the middle, resembling " navicellse," 



0-125 X 0-03 ; 012 x 0-035. 

 {<■) Cylinders with a conical termination, 015 x 0-04 ; 0*15 x 0-02. 

 {<]) Spindle-shaped with one-half expanded and bifurcated, 0-175 x 0-03 ; 



0-175 X 0-045 ; 015 x 002. 

 {(') Quartettes, 0-15 x 0-04 ; 0-15 x 0-03. 



(/) Irregular and intermediate types, 0*2 x 0-1 ; 0-175 x 0-04 ; 0-15 x 003. 

 In C. lutkenii the ends of the spicules are never divided. 

 The colour of the colony is creamy- white. 

 Locality : Orissa Coast, Marine Survey. 



Cavernularia andamanensis, n. sp. Plate IX. fig. 3. 



Two incomplete colonies representing only the upper portion of the trunk. 

 Both are cylindrical in shape, and are 28 mm. and 21 mm. in length and 10 mm. 

 and 6-5 mm. in diameter respectively. The axis extends to the very tip of the 

 colony and is quadrangular in cross-section, with the sides slightly incurved. 

 In the larger specimen it is 1-75 mm. broad, in the smaller 1-25 mm. 



The colonies are different in texture and in degree of contraction. The 

 larger is very soft and spongy and all the polyps are withdrawn. The polyps 

 occur almost uniformly all over the surface. The openings are circular and 



