PROM A DREDGING IN THE WEDDELL SEA. 
701 
only. Pores on tube walls in two rows, pores 5 or 6 per mm. Centre of cup filled 
near the base by coralloidal tissue. All skeletal structures sometimes thickened by 
secondary growth. 
The specific name is due to the slender character of the walls and tubes. 
Coscinocyathidse. 
Coscinocyathus, Bornemann, 1884. 
The genus as described by Bornemann is characterised by the presence of 
horizontal tabulae which mark it off from other forms of the group. The pores 
on the inner wall are defined as larger than those on the outer, but Taylor showed 
that this is not a constant feature. The Australian species described by the latter 
author have pores on both walls equal in size, and the Antarctic specimens conform 
to the Australian type rather than to the Sardinian. These Weddell Sea specimens 
fall into two categories, very distinct from one another and from all previously 
recorded Coscinocyathidee. The mode of fixation of both types has been determined, 
and on this character alone they are easily distinguished. 
Coscinocyathus fultus* n. sp. 
Although only one complete specimen of this form and the tip of a second have 
been noted, the general character of the skeleton has been elucidated. The specimen 
from which most of the skeletal details have been obtained lay partially exposed on 
the side of the block. This weathered surface is illustrated by PI. V, fig. 50, where 
the septa, the tabulae (; t ), and porous inner wall (i.w.) are all obvious. The tabulae 
at once place the form among the Coscinocyathidae. 
In transverse section most of the salient features become visible (PI. VI, fig. 60). 
At a a small oval body, with its interior filled by convoluted partitions, is seen in 
close association with the main cup, and in a lower section, represented by fig. 61, 
several of these bodies are obviously connected to the surface of the cup. They 
become confluent round the periphery, and form a zone of vertical partitions sur- 
rounding the outer wall of the latter. Such offsets effect fixation of the whole 
structure. They occur in several series, and as new series are added the outer wall 
of the lower set is occluded, so that a series of walls, concentric with the outer wall 
of the cup, crosses the zone of vertical partitions (PI. VI, fig. 60, p, p). These con- 
centric walls are again seen in fig. 62, p, and it will be noticed that each reaches 
a higher level on the cup than does the one below. The vertical partitions 
are continuous across the concentric walls and are arranged perpendicularly to 
the latter. 
The question as to the function of these bodies is more easily answered in this 
case than was possible in the case of Spirocyathus atlanticus. As far as Coscino- 
* Lat. fultus, supported. 
