on the Genus Paleacis. 215 
Whether the sections are taken across the cups in a direction 
perpendicular to their long axes, or corresponding with these, 
the appearances presented are the same. In both cases the 
calcareous tissue of the skeleton appears to be penetrated by 
minute microscopic tubuli, which run at right angles to the 
cups, and which are much more largely developed and more 
conspicuous in some parts than in others. The layer which 
forms the immediate floor and walls of the cups is not lacunar 
or trabecular, but is traversed by innumerable minute tubules 
(Pl, XII. figs. 7,8, 6), which are directed outwards in a series 
of parallel bands, the tubules of each band having a more or 
less penniform disposition with regard to a central tubule. 
These tubules doubtless open on the floor of the cup ; but their 
apertures are too minute to admit of recognition in any of our 
specimens. Apart from the layer which lines the cups, the 
rest of the skeleton is made up of a more or less open cellular 
or trabecular tissue (Pl. XII. figs. 7, 8, c), consisting of irre- 
gular lacune of various sizes, separated by calcareous parti- 
tions, but doubtless more or less freely communicating with 
one another. By the opening of these lacune upon the 
general surface are formed the large pores which are so com- 
monly seen on the lower aspect of these fossils, and less often 
upon the upper surface as well. ‘The calcareous partitions 
between these lacune are likewise minutely tubulated, though 
this structure is not nearly so well developed or so conspicuous 
as in the floor of the calices; and the tubules run directly 
across the partitions and thus place contiguous lacune in 
communication. Of P. cunetformis our knowledge is not so 
complete ; but the structure seems to be essentially the same 
(Pl. XII. fig. 14). The calcareous tissue of the skeleton is 
traversed by microscopic tubuli; but the general texture is 
more compact, and the trabecular tissue is but slightly deve- 
loped, such lacune as are present being remote and separated 
by a considerable thickness of compact tissue. In some cases, 
also, there proceed from the depressions between the surface- 
ridges larger canals, which become gradually smaller as they 
pass inwards, and which do not appear to actually reach the 
interior of the cups. 
A ffinities.—Paleacis, as we have mentioned, has been gene- 
rally regarded as a “ perforate’? coral; but the microscopic 
structure would completely bear out Prof. Verrill’s view that 
it cannot be referred to the Actinozoa. It seems, on the con- 
trary, to exhibit a minute structure which would place it 
somewhere amongst the Protozoa (including the sponges in 
this subkingdom), and which certainly cannot be paralleled 
among any of the true corals. The general reticulated struc- 
