PROF. THOMSON AND MR. McQUEEN REPORT ON THE ALCTONARIA.NS. 93 



The autozooids are large and well-marked. Towards the periphery of the 

 capituluin they are closely aggregated in rows parallel to the free border, 

 the individuals of adjacent rows alternating. Towards the centre of the 

 capitulum they become sparser. A converse distribution of the siphonozooids 

 is to be noted. 



Tow^ards the centre the siphonozooids are very numerous ; as many as C 

 to 13 can be counted in a straight line between two adjacent autozooids : 

 peripherally only 1 to 3. 



The spicules agree with Marenzeller's figures. 



The following measurements were taken of length and breadth in milli- 

 metres : — 



Cortical spicules from the lobes of the capitulum : 



Clubs: 0-22 X 0-06; 0-175 X 0-025 ; 0-15x0-025; 0-13x0 04: ; 0-1 x 



0-015. 

 Bods: 0-35x0-025; 0-29x0-025; 0-26x0-02; 0-21x0-025; 0-15 x 



0-015. 

 Spindles: 0-27 x 0-03; 52 x 0-03 ; 0-22 x 0-04 ; 0-17 X 0-02; 0-15 x 0-02; 

 0-075x0-02. 

 Spicules from the autozooids : 



Rods: 0-28x0-02; 0-27x0-02; 0-26x0-02; 0-25x0-02; 0-21x0-01. 

 Cortical spicules from the trunk : 



Tubercnlate spindles : 0-8 X 0-15 ; 0-8 x 012 ; 0-78 X 0-16 ; 0-74 x 0-12 ; 

 0-G8X0-14 ; 0-62x0-12 ; 0-55 X 0-15 ; 0-5x0-1 ; 0-47x0-075 ; 

 0-44x0-06; 0-45x0-075; 0-35x0-075. 

 Slightly spinose spiniUes : 0-39 x 0-04 ; 0-34x0-04 ; 0-32 x 0-04 ; 0-3 x 



0-06 ; 0-15x0-03. 

 Clubs: 0-24x0-06; 0-2x0-05; 0-18x0-05; 0-15x0-03; 0-12x0-05; 



0-1x0-04. 

 Smooth spindles: 0-4x004; 0-275x0-03; 0-23x0-03; 0-22x0-02; 

 0-12x004. 

 The colour in spirit is light to medium brown. Mr. Crossland notes that 

 the colour of the li\aug colonies was greenish brown, but that the tentacles 

 were white in some. Consequently the fully expanded colony, seen from 

 above, often appeared white. 



Locality. — Suakim Harbour ; growing in proximity to coral, Sherm Shekh. 

 Previously recorded from Australia, Red Sea, Tonga Island, Viti Island, 

 Maldive Islands. 



SCLEROPHTTUM GAEDINERI, Pratt. 

 See E. M. Pratt : " The Alcyonaria of the Maldives," in Gardiner, Fauna and Qenp:raphy 

 of the Maldive and Laccadive Archipelagoes, ii. (1903) p. 527. 



Several specimens belonging to this species illustrate how a colony becomes 

 gradually more complex in its structure with increased growth. A young 

 colony is represented by an elliptical mass 7-5 cm. by 5-5 cm.; from its 



[53 J 



