GENEEA OF THE ALCTONAEIA STOLOKLFEEA. 343 



The stolon is composed of thin strands varying from 1 to 3 mm. across, which 

 coalesce at intervals to form small plate-like expansions. The polypes are of various 

 sizes, the largest I have measured being 8 mm. long, with a maximum of 2*5 mm. in 

 breadth. They have very thick walls, due to an extreme development of the mesoglcea. 

 No grooves or lines of any kind mark externally the insertion of the mesenteries. 

 The tentacles are long and pointed in life, and provided with numerous densely 

 crowded pinnse. The polypes are not capable of any very great contraction, but the 

 crown of tentacles can be introverted into the anterior part of the polype-walls. 



As I have had at my disposal such a small specimen I have not made as complete a 

 study of the anatomy of this species as I should wish, but in the fragments of the 

 stolon and polypes 1 have examined with the microscope I have not been able to find 

 any trace of spicules. It is possible that they exist, for I find that it is never safe to 

 state that there are no spicules in any species unless several polypes and a large piece 

 of the stolon have been boiled in potash and the residue examined with the microscope. 



The colour of the stolon and body-walls is the usual dull olive-brown, but the 

 pinnse of the tentacles are bright green. 



When examined alive with the polypes expanded this species is one of the most 

 beautiful, delicate, and graceful Alcyonarians I have ever seen. 



Locality. Talisse Island, N. Celebes ; shallow water. 



Clavulaeia vikidis, Quoy & Gaimard. (Plate XLIX.) 



I published, in the 'Proceedings' of the Eoyal Society, 1886 (lo), a preliminary 

 account of some observations on this species that I made when I was resident in Celebes. 

 I then pointed out the existence of the remarkable tubes connecting the polypes, and 

 the similarity of the expanded polypes, both in form and colour, to those of Tubipora. 



Since my return to England I have made a few more observations upon its anatomy. 



The species may be found in abundance on most of the coral-reefs of North Celebes, 

 and probably occurs on the shores of nearly all the islands of the Malay Archipelago. 



Quoy and Gaimard, who originally described the species, found it at Vanikoro, and 

 Wallace obtained some specimens, which are now in the British Museum, from the 

 Aru Islands. 



Its usual habitat is, like Tubi^ora, on the shore side of the reef, where it is left 

 exposed to the air at low water of spring tides. It occurs either in large clumps 

 five or six inches in height and over a foot in diameter, or in small creeping colonies 

 clinging to dead water-worn coral branches. 



When dried in the sun it leaves a firm but brittle skeleton, composed of a plexus 

 of irregular branching fibres, which fuse into a continuous sheath in the lower parts. 

 This skeleton retains the original form of the contracted colony. 



In colour the expanded polypes are either olive-brown or green, or any of the 

 intermediate colours between the two. 



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