HICK AND CASH : FOSSIL FLORA OF HALIFAX. 
377 
phylloides in addition to what we have already pubhshed. In some 
of the more recently acquired examples however, which are appar- 
ently young-er than the orginal form, the pith is much reduced in 
relative size, while in others it seems to be altogether absent. In 
these last, the vascular wedges appear to meet in the centre of the 
axis, but they still retain their radial arrangement, and have evidently 
been developed centiifugally. 
A more important point, perhaps, than the diminution or absence 
of the pith, is the state of the cortex in the earlier stages of devel- 
opement. From some of our younger specimens it would seem that 
at first the cortex forms a continuous mass of thin-walled parenchyma, 
in which neither air cavities nor radiating plates have as yet been 
differentiated. The specimens are not decisive as to the mode in 
which these are afterwards formed, but they suggest the idea that 
the process is the same as that which obtains in recent aquatic 
plants. In these, the air cavities arise schizogeuously, that is, by 
the splitting of the cellulose lamelliB which form the walls of the 
cells, as may be readily seen in young peduncles of Nwphar^ and the 
stems of the aquatic plants already mentioned. In the phenomena 
presented by the earlier developmental stages then, we have a 
confirmation of the justness of our original views, so far as they had 
reference to the aquatic nature of Myriophylloides. 
FUETHER NOTES ON NEW SPECIES, AND OTHER YORKSHIRE 
CARBONIFEROUS FOSSIL POLYZOA DESCRIBED BY PROF. JOHN 
PHILLIPS. BY GEORGE ROBERT VINE. 
The Genus Calamopora was founded by Dr. August Goldfuss* for 
the reception of species that had been previously described by 
authors as Tuhipora, and by Lamarck as Favosites and AlveoUfen. 
The definition of the Genus is very simple, but by no means satis- 
factory, as it is quite clear, that even by the author himself, many 
* Petrelracta Germanaj. 
