254 



PROF. S. .1. HICKSON ON THE 



[Apr. 5, 



mounting them whole and by making series of vertical sections. 

 The following is a list of the specimens examined : — 



" Dichotoma." „ „ 



And a specimen of " Plicate " form obtained by myself in Celebes. 



The preparation and examination of these Millepores has extended 

 over a period of twelve years, with the result that I have failed to 

 find any constant difference between them that can be used for the 

 separation of the genus into species. 



The structm-e of the gastrozooids and the dactylozooids is 

 essentially the same in all the specimens examined, but the size 

 varies somewhat, according to the position from which the prepara- 

 tions are made — those at the growing-edges being smaller than 

 those at the base, &c. The canal-system is the same in ail 

 specimens. Zooxanthellse of exactly the same size are always 

 present in the superficial canals. I have observed the two different 

 kinds of nematocysts, the large and small figured by Moseley, in all 

 my preparations. Many of the Millepores are known to sting 

 badly, and have received popular names in various languages 

 expressive of this feature, but Mr. Gardiner iuforms me that one 

 form in Funafuti did not sting. " It was at its base rather over- 

 grown by weed, and above, curiously enough, it did not sting, and 

 was the only one m Funafuti that did not." ' 



It is not known whether both the large and the small nematocysts 

 possess the stinging-power, or whether it is confined to only one 

 kind. The small nematocysts are confined to the tentacles of the 

 gastrozooids and dactylozooids, and the largo nematocysts, when 

 ripe, occur in the superficial coenosarc bet\Neeu the pores, but are 

 specially crowded in the neighbourhood of the gastropores. 

 Moseley's description of these features in MiUe])ora is correct for 

 all specimens I have examined. The size and the position of 



' Extract from a private letter. 



