FROM A DREDGING IN THE WEDDELL SEA. 
705 
Conclusions. 
At the outset it must be admitted that this research has not led to any more 
definite ideas regarding the type of organism which secreted the Archseocyathus 
forms of skeleton. The method of cutting sections in definite directions has allowed, 
however, of a more minute description of certain skeletal types. In several forms 
the means of fixation of the skeleton have been determined, and these are not con- 
stant for all species of the same genus, while closely similar methods of fixation occur 
in different genera. Thus Spirocyathus atlanticus and Coscinocyathus fultus have 
root-like emergencies acting as stout supports (perhaps also as stolons), while 
Coscinocyathus fultus and C. endutus have very different methods of fixation. 
It is suggested that the fixing strands may have functioned as stolons producing 
a vegetative increase in the number of individuals, but no case has been seen where 
new cups actually arise from these emergencies. Taylor, however, records a cup 
arising from exothecal lamellae (fixation lamellae) in Archseocyathus Sellicksi* though 
even there it is not clear whether the new cup arose from the exothecal structures 
or was merely fixed to them. Apart from the fixation structures, there are one or 
two marked features in this fauna from Antarctic regions. In the first place, the 
specimens are small ; secondly, they show, in the majority of cases, marked thickening 
of the walls near the base ; and thirdly, there are a great number of specimens (and 
these belong to different genera and species) in a very small amount of material, i.e. 
the fauna was abundant and varied, but the individuals small in size. The' largest 
example is under 30 mm. long, and the greatest diameter noted in any cup is 10 mm. 
or thereby. This compares very unfavourably with specimens from any recorded 
locality, save only the other Antarctic record, from 85° S. on the Beardmore Glacier. 
Despite the small size, the skeletal characteristics are constant and quite comparable 
with similar forms from other regions. 
Thickening of the walls and septa occurs near the base in several species, and this 
is accompanied by a partial filling of the central cavity by ingrowths from the inner 
wall. Such infilling may be an irregular coralloidal mass ( Thalamocyathus trachealis, 
Coscinocyathus fultus, etc.) or a series of twisted tabulae (continuations of similar struc- 
tures crossing the intervallum), with the interspaces filled by more irregular tissue 
(Protopharetra polymorpha, PI. Ill, fig. 36). Both of these characters seem best 
regarded as gerontic features, or as indicating that the specimens were at any rate 
mature. In either case, when combined with the small size of the specimens, they point 
to the conclusion that the conditions under which the organisms lived were far from 
favourable to their growth, maturity supervening while the organism was small ; or, 
what amounts to the same, growth being exceedingly slow. Such a conclusion is 
confirmed rather than refuted by the fact that so many varied types occur in a very 
small volume of material. It has been pointed out in various records that great 
* Merri. Roy. Soc. S. Australia, vol. ii, part ii, 1910, text-fig. 9. 
TRANS. ROY. SOC. EDIN., VOL. LII, PART IV (NO. 27). 
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