1898.] OF MILLEPOKA FKOM FUNAFUTI AND BOTUMA. 833 



Facies " camplanata." 



The spirit-specimens of this facias were collected in shallow 

 water at Funafuti, and are, like the dried specimens, very consider- 

 ably affected by barnacles and other parasites. Unfortunately the 

 state of preservation was not perfect, and many details of histology 

 could not be made out at all. 



The preparations are, however, of very great interest, as showing 

 medusse bearing spermacytes. Many of the meduste are quite loose 

 in their ampullge, and are shaken out of them during decalcifi- 

 cation, so that they can be mounted whole. The largest medusae 

 mounted in this manner were about '57 mm. in diameter ; but as it 

 is impossible to prevent them from being slightly compressed as 

 the Canada balsam dries, we may consider that their diameter is 

 only a little over § mm. This is almost exactly the same size as 

 the male medusse in Professor Haddou's collection. 



Facies '■'■ plicata" from Eotuma. 



Several specimens of this form were killed in corrosive sublimate, 

 washed with iodine, and preserved in spirit. They are all in an 

 excellent state of preservation. 



Many of the specimens show on the surface shallow round 

 depressions about g mm. in diameter, which so closely resemble the 

 scars of the ampullae seen on the dried coralla, that there can be 

 no doubt that they represent the spaces from which the medusas 

 have escaped. The depression is, however, overgrown by ectoderm 

 and possibly a certain amount of the eudoderm's canal-system as 

 well, so that when the specimens are decalcified all trace of these 

 depressions disappear. In studying the ampullae of dried coralla 

 I was much struck with the fact that they are never found anywhere 

 but in the superficial layer of the corallum, and I was inclined to 

 believe at one time that when the colony of a Millepore had once 

 produced medusae it died. This view, however, was not confirmed 

 by the examination of Prof. Haddou's material from Torres Straits, 

 in which the medusa-bearing colonies showed every sign of being 

 in a thoroughly healthy and actively feeding condition. 



The Millepores from Eotuma confirm the opinion that my former 

 view was wrong, since several of the gastrozooids contain food in 

 the form of minute Crustacea, and the ectoderm and other tissues 

 are all thoroughly sound and healthy. The specimens prove, 

 moreover, that when the oucer wall of the ampulla is broken to 

 allow the escape of the medusa, the ccenosarcal tissue covers over 

 the gap, and in time obliterates all signs of it. 



It is quite impossible, of course, to form any estimate of the 

 length of time that elapsed from the escape of the medusEe until 

 the specimen was collected, but it is noteworthy that not a single 

 medusa remains. 1 have decalcified more than three quarters of the 

 material sent to me, and have searched through the whole of the 

 material thus decalcified with a powerful lens, but I can find no 

 trace of a medusa, and in the sections I have cut there are no 

 signs of any sexual organs. 



