832 PEOF. S. J. HICKSON ON SPECIMENS [NoV. 15, 



to which the different parts of a colony are exposed in their natural 

 position on the reef. 



II. Spirit-specimens. 



Facies " rcnnosa," 



Mr. Gardiner killed in corrosive sublimate and preserved in 

 spirit some specimens of this facies which he obtained in 7 fathoms 

 of water at Funafuti. It was clearly of importance to see if the 

 soft parts of the deep-water ramose forms differ in any degree 

 from the shallow-water lamellate forms. 



I found the material in excellent condition for the investigation, 

 as many of the gastrozooids appeared to be fully expanded, and some 

 of the dactylozooids jiartially so, and I was able in consequence 

 to see in a particularly favourable manner the small and large 

 nematocysts, the tentacles, and the histology of the polyps. 



The nematocysts are, so far as I can judge, exactly the same as 

 in all other Millepores. I have been unable to find any of the large 

 kind exploded in my preparations, and consequently I can say 

 nothing about the character of the thread. The condition of these 

 large nematocysts varies considerably in different specimens of 

 Millepores ; sometimes they may be found in all stages of develop- 

 ment, but more frequently they are nearly all in one stage. 

 Sometimes nearly all the ripe nematocysts of this kicd may be seen 

 with their threads attached to them, sticking into the superficial 

 ectoderm or just below it ; in others, again, not a single exploded 

 nematocyst can be found. In the specimens I am now describing 

 the absence of exploded nematocysts may be accounted for by 

 believing that they were washed off in coming up in the dredge, 

 but I am not certain that that explanation is quite satisfactory. 

 The unexploded nematocysts measured '02 mm. x "025 mm., 

 i. e. the exact size of the large nematocysts of other Millepores. 

 The manner in which the tlu'ead is coiled up inside the vesicle is 

 also the same as in other Millepores. 



The small kind of nematocyst which is found characteristically 

 in the tentacles of gastrozooids, but occurs also more rarely in the 

 coenenchym, varies in size considerably, but the largest of them are 

 exactly | the length of the large kind of nematocyst, and are conse- 

 quently normal in size. In one instance I have seen the swollen 

 base of the thread armed with three spines, as described and figured 

 by Moseley. Tliere is no reason, therefore, to suppose that the 

 nematocysts of this form diflrer from those of other Millepores. 



As in all other specimens I have examined, the canals contain 

 numerous zooxanthellae. They are a good deal more crowded than 

 usual in the superficial canals, as might be expected in forms living 

 in deeper and consequently darker water. Each zooxanthella is 

 perfectly spherical in form, being 'Ol^S mm. in diameter. They 

 exhibit no peculiar features. 



The gastrozooids and dactylozooids are exactly the same in all 

 essential features as the gastrozooids and dactylozooids of other 

 well-preserved Millepores which I have examined. 



