318 PROFESSOR P. M. DUNCAN ON THE 
Genus Batuycyatuus, Milne-Edwards & Jules Haime, 1848. 
BATHYCYATHUS ATLANTICUS, Duncan. (Plate XLVIII. figs. 1, 2.) 
The corallum is circular in outline at the base, but becomes compressed above, so 
that the axes of the calice are very unequal. 
The corallum is in the shape of a reversed and compressed cone. 
The calice is elliptical in outline, and the great axis is on a lower plane than 
the smaller. 
The septa at the reticular margin are exsert, and project outwards so as to give a 
very open aspect to the deep calice. The septa are unequal, and the primary and 
secondary laminz are very prominent. The septa of the last cycle are larger than the 
penultimate. ; 
There are four complete cycles of septa, and also three derived septa from the fifth 
cycle, so that there is an appearance of thirteen sets of three septa and thirteen large 
septa. The septa are granular, and ornamented with radiating lines of granules. 
The pali are large, distinct, prominent, very granular, and are placed before the 
tertiary cycle. 
The columella consists of essential and ribbon-shaped processes, and is well developed 
and deep in the fossa. 
The coste are broad, granular, and subequal; but those of the largest septa are 
distinctly prominent far down towards the base. 
Height of corallum 1 inch to 14 inch; length of calice 385 inch; breadth of calice 
75 inch. 
Some fragmentary specimens evidently belonged to larger forms. The coral was 
found in No. 17a and No. 17 dredgings, in the second expedition of the ‘ Porcupine, 
and in 740 and 1095 fathoms. : 
The genus Bathycyathus is closely allied to the Caryophyllie ; and were it not for the 
peculiar structure of the upper part of the septal apparatus, it would be included 
amongst them. 
The species hitherto described, viz. Bathycyathus chilensis, Ed. & H., B. indicus, 
Ed. & H., and B. sowerbyi, Ed. & H., have five complete cycles of septa. The first two 
are recent forms, and are probably identical, and were dredged up off the coast of Chili, 
at a depth of 80 fathoms, and off Juan Fernandez. 
The fossil species (Bathycyathus sowerbyi, Ed. & H.) of the Upper Greensand is never 
found in a perfect state, and is closely allied to the recent forms. 
Hence the new species, with its defective fifth cycle, is less closely allied to the 
Cretaceous type than its Pacific congeners. The genus has not been found represented 
in any Upper Cretaceous or Tertiary strata. 
