FROM A DREDGING IN THE WEDDELL SEA. 
691 
at intervals on larger individuals. Length up to 90 mm. Cup ends in pointed 
spitz, anchoring material not preserved or . wanting. Outer wall a delicate porous 
lamina ; pores 8 per mm. Wall sometimes invested by a thin layer almost closing 
the pores. Septa numerous, stout, regular, with perforations in rows and about 
4 per mm. in the row. Aperture of perforation small, hence they appear more 
remote from one another than the pores of inner or outer walls. Inner wall of 
ring-platforms firmly fixed to inner ends of septa in a vertical series, grooved on 
top. Pores delimited by septa and platforms ; 5 per mm. Below each shelf a 
row . of closely set denticles forming comb-like structures partially closing over 
the pores. Base of central cavity, i.e. earliest part of cup, filled in by coralloidal 
growth from the platforms. 
Thalamocyathus infundibulum, Bornemann. 
1884. Archseocyathus infundibulum , Bornemann, Geol. Zeitscbr., p. 703. 
1886. „ ,, ,, “ Yersteinerung Sardinien,” Nova Acta der Ksl. Leop.- 
Garol. Deut. Akad. der Nat., vol. li, p. 52, pis. ix, 
x, xi, xiv. 
Among the smaller forms obtained, one, represented in PI. Ill, fig. 30, can be 
referred to the above species. In the only section prepared the cup is cut longi- 
tudinally, and the pores of both inner and outer walls are shown in places. These 
are respectively 4 per mm. and 10 per mm., numbers which correspond with those 
given in Bornemann’s original description. The septa do not seem to be porous. 
The shape is conical and also conforms to the original type. Some of the small 
transverse sections, which occur here and there in the material, may possibly be 
referred to this species, but there is no certainty in the matter until longitudinal 
sections are available. No rooting structures are visible in the specimen obtained. 
Thalamocyathus ichnusse, Meneghini. 
1881. Archseocyathus ichnusse, Meneghini, Atti della Societa Toscana, p. 201. 
1884. ,, „ Bornemann, Geol. Zeitschr., p. 704. 
1886. „ „ ,, “ Yerstein. Cambs.,” Nova Acta der Ksl. Leop.-Carol. Deut. 
Akad. der Nat., vol. li, p. 58, pis. ix, x, xi, xii, xiii, and xiv. 
Another of the forms of which only a single example has been found is T. 
ichnusse. As in the case of T. infundibulum, the sole section is a longitudinal one. 
Fortunately, the walls and the septa are shown in places, so that the details can 
be determined with fair certainty. In PI. Ill, fig. 31, this section is represented, 
and it evidently expanded greatly towards the top, as do the Sardinian examples. 
By measurement and calculation from Bornemann’s figures and statements, an 
estimate of the number and arrangement of pores on the skeletal elements of his 
type has been attained. The inner wall has 6 or 7 pores per mm., while the outer 
