vine: CARBOXIFEROrS AND PERMIAN POLYZOA. 
79 
of structure indicated by Mr. Ulricli in his American examples of 
the Family and Genus, Mr. John Young remarks (Bibliog. 1887. 
ante, p. 464) : — " The chief character, however, that distinguishes 
the organisms noticed in this paper, ( Cystodictya ixirallelci and 
raricosta, Goniocladia cellulifera, and Hifphasmapora Baskii), is in 
their having the interstitial spaces between the cells filled with small 
vesicular tissue, or curved cells, a character not generally known to 
exist amongst undoubted forms of the Polyzoa." 
I. Superficial characters of Cystodictya parallela, Phillips, sp. 
In describing the above species I have already referred to its 
facial features. Generally speaking, only small fragments are found 
in the Yorkshire shales, and in other localities, even the best, it is 
rare to find examples more than half-an-inch in length. The specimens 
given by Phillips in the Geol. of Yorkshire, are of fairish dimensions, 
and Mr. Young, as already quoted, speaks of fragments from two to 
three inches in length. In pi. ii., figs. 20 to 23, I have depicted 
several modes of branching in this species, from fragments in my 
possession, and as neither Phillips nor Young allude to ''ramifications," 
these will be so far interesting. 
II. Zoarium in section. I have already directed attention to the 
minute structure of the Zoarium of Htktopora ? (Ptilodictya) lonsdalei, 
Vine 1883-4, Biblio. ante. p. 37, and furnished ample illustrations of 
the same. In dealing with the structures of C. parallela I shall work 
along the same lines but with rather greater fullness. Whenever 
fair examples of this species are sectioned, we find, as already quoted 
a most peculiar combination of characters, both in the cells and 
Zoarium, not met with in the Silurian Stictoporidse group. In the 
first place the laminar axis in Cystodictya is altogether wanting, or 
replaced by a basal attachment of cell to cell in a zigzag form, both 
in the transverse (pi. i., f 12 and 13), and longitudinal direction 
(pi. i.. f 3). In Stictopora?' lonsdalia the so-called ''laminar axis" is 
straight both in the longitudinal and transverse section. The 
" tubular" cells, also, are different in both species, and these, 
separately, may be regarded as characteristic of the two types of cell 
structure in some of the allies of both species found in Carboniferous 
and Silurian horizons, in this country and in America. There is, 
