830 PROF. S, J. HICKSON ON SPECIMENS [NoV. 15, 



Alcyonium digitatum, being thickly palmate with short obtuse and 

 warty branches. 



The most striking feature about this Millepore, and fragments of 

 others which 1 judge must have had a similar form, is the great 

 thickness of the " live " corallum. The apparent thickness of 

 Millepore branches is often very misleading, for it may be observed 

 that in many specimens the apparent thickness is due to the 

 Millepore having grown over a dead coral and completely en- 

 crusted it. 



Some of the branches of this coral are actually more than 

 22 mm. in diameter. They are the thickest branches of live 

 Millepore corallum I have had the opportunity of examining. 



I have satisfied myself that in most cases the pores are continuous 

 from the surface to the centre without any break but that of the 

 tabulae. In some of these pores there must be at least 35 tabulae, 

 which is more than twice as many as in any other Millepore I have 

 carefully studied. 



The texture of the corallum is light and brittle, the colour white, 

 and the surface almost free from barnacles and worm parasites. 



All of these features suggest that the conditions under which 

 these specimens lived were particularly favourable, that the growth 

 of the corallum ^vas rapid, and the conditions of its tissues so 

 healthy that it could resist the action of the larvae of parasites. 



Mr. Gardiner tells us that Millepora of the facies '' esperi" 

 occurs most abundantly in the lagoon on each side of the passages 

 to windward, and never where it would be directly exposed to the 

 rush of the tide. In this situation it forms large clumps, commonly 

 as much as 7 or 8 feet in diameter, rising out of 5-10 feet of water 

 to a foot from the surface at ordinary low tide. It also occurs 

 sparingly by the passages to leeward, and on some of the more 

 exposed shoals in the lagoon. 



The lightness and brittleness of these specimens form a very 

 striking feature, and it occurred to me that it might be expressed in 

 figures fairly accurately by the specific gravity, which was found 

 to be 2-53. Compai-ed with other Millepores this is decidedly low. 

 The sp. pr. of a fragment of facies <■' ramosa" was 2-9, of a 

 complanate form from Funafuti also 2-9, of a complanate form in 

 the Manchester Museum 3- 17. 



Facies " complanata." 



There is one large specimen, 20 cm. in height, which resembles 

 the form of growth of M. complanata, and there are several frag- 

 ments similar to it in the collection. Mr. Gardiner says it is not 

 common in the lagoon, being found only on certain shoals close 

 together towards the E. side. 



The large specimen consists of five coalescent lamina;, the fre 

 edges of which are di\ ided in some places into short, blunt digita- 

 tious ov tubercles. The thickness of the laminae varies considerably, 

 but the average thickness is about 1 cm. The average number of 



