168 PEBCr SLADEN TRUST EXPEDITION. 



Pamily CornulariidsB. 



Genus SYMPODIUM. 



1. Sympodium ccBruleum, Ehrenberg. (Plate 12. fig. 2.) 

 For description see : — 



Klunzinger: Korallthiere des Rotheu Mecres (1877), p. 42, pi. 3. fig. 5. 



Several bluish-green colonies, forming flat or cushion-like encrustations on stones, 

 Avith polyp-bodies retracted into the ccenenchyina (about 1-5-2 mm. in diameter across 

 tlie mouth), Avith minute spicules like blood-corpuscles. 



Localities. Coetivy ; Egmont, 6-7 fms, lagoon. 



Previously recorded from Tumbatu, East Africa, Red Sea, Zanzibar. 



2. Sympodium salomonense, sp. n. (Plate 12. figs. 11 & 12 ; Plate 15. figs. 15 a, fi.) 

 The collection includes, among its most puzzling specimens, four white and orange 



colonies from 12 to 16 mm. in height, with an average breadth of about 8 mm. Their 

 appearance suggests an Alcyoniid of the type of Erythropodium indicum (Thomson and 

 Henderson). Examination shows, however, that there is an axis of stony hardness, over 

 which a very thin coenenchyma is spread. The polyps, which are completely retracted 

 into the coenenchyma, bear no real relation to the axis beneath. The specimen, in fact, 

 must be interpreted as a membranous Alcyonarian, which has formed a thin encrustation 

 over the weathered base of a madreporarian coral, the thecae of which are now occupied 

 by the polyps of the Alcyonarian. The general appearance of the colonies is well 



shown in the figures. 



Tlie polyps are indicated externally by bright spots of orange colour, 1-2 mm. in 

 diameter. The polyp-openings are surrounded by very low, eiglit-rayed calyces, 

 separated from one another by intervals of 2-4 mm. The surface of the calyces is 

 densely crowded with orange-coloured double spindles and " quadruplets." The white 

 [)olyps are deeply sunk into the coral pits, and appear to be entirely destitute of spicules. 

 In some cases they contain numerous ova of large size. 



In the areas between the calyces the coenencliyma is so thin that the colour and 

 markings of the subjacent coral can be seen through it : here the spicules are much less 

 numerous and are either colourless or yellowish. 



The double-spindles are broad in proportion to their length, especially in the case of 

 those of a reddish colour: 'OTX-OS mm., 06 X 035 mm., •04X'015 mm. The body of 

 the spindle bears two whorls of tuberculate warts, each wart having about ten short, 

 sharp tubercles. Each end of the spindle bears similar tubercles grouped on a wart-like 

 knob. In many cases this terminal knob may be double, or there may be accessory 

 knobs between the whorls and the ends. 



The " quadruplets " are four-cornered spicules with an axial cross, each corner bearing 

 one or more tuberculate warts. In one instance the warts had developed so that the 

 result was a six-cornered, though four-rayed form. A five-rayed type was also observed. 

 The average dimensions of the " quadruplets " are 05 to -06 mm. 



