276 Cincinnati Society of Natural History. 
At intervals the surface exhibits the apertures of one or two cells, 
which are much larger than the average, and may represent ocecia. 
The typical and only known species of this genus is simple enough 
in its structure, yet despite its simplicity, I have not been able to de- 
termine its affinities in‘a manner satisfactory to myself. The genus is 
clearly a member of the Treposromata, but of what family of the sub- 
order is not so readily determined. It possesses one point of structure 
common to all of the Ptilodictyonide and Stictoporide; but in all other 
respects the genus differs so widely from those families that I can not for 
amoment admit that Andsotrypa is referable to either. The point of 
resemblance is found in the diaphragm crossing the tube-cavity at the 
base of the erect and thickened portion of the zoocia, which, I believe, 
constitutes the floor of the “matured” cell. The same character is also 
present in the Rhabdomesontide, though not so strongly developed. 
This family, lately established by Mr. Vine, for the reception of the 
genus Rhabdomeson, Y. and Y., is, I think, warranted by the peculari- 
ties of cell-structure, and not upon the “central red,’ that character 
being, in my opinion, of only generic value at the most, I have ex- 
amined the #. gracile, Phill., the type of the genus, and find that, 
aside from the axial tube, the genus differs in no other respect from 
Meek’s Rhombopora. As I intend to discuss the relations ef this 
family at some length, in the next number of this Journat, I will not 
further anticipate my conclusions, than to say that Anisotrypa ap- 
pears to be more nearly related to Rhabdomeson and Khombopora, 
than to any other forms known to me. 
ANISOTRYPA SYMMETRICA, wv. sp. (Pl. XIII, figs. 5-5¢). 
- Zoarium ramose, branches hollow, consisting of one or two distinct 
layers of cells, the inner sides of which are lined by a thin, slightly 
wrinkled epitheca; diameter of branches varying from .15 to .3 of an 
inch; thickness of each layer of cells, .03 of an inch, or a little less. 
Zocecia hexagonal or pentagonal, with a very regular arrangement in 
groups, the centers of which occur at intervals of about .12 of an inch. 
From the center of each group, usually marked by an extremely large 
cell, to a point midway between the groups, they gradually diminish in 
diameter from »,th to j5th of an inch. The diameter of the large cen- 
tral cell, which is probably an ocecium, may exceed 34th of an inch, 
though it is usually a little less. The boundary of the zocecia is 
marked by a slightly elevated line, from which the walls slope down- 
