Revision of Bryozoan Genera.—Cumings. 203 
ing the mouths of the zocecia over patches of the surface of 
the zoarium; 5) the number of the mesopores. 
The writer has recently come into possession of material 
that throws new light upon each of these five characters. 
The genus, Dekayella Ulr. is said not to contain any truly 
frondescent species. The Cincinnati group affords, however, 
such a species. At the base of the Platystrophia zone (Lor- 
raine) near Manchester station (C. C. C. & St. L. R. R., Chi- 
cago & Cincinnati Division,) Dearborn Co., Indiana, occurs 
the variety of Dekayella ulrichi (Nich.) next described.” 
Dekayia ulrichi-lobata n. var. 
PL. IX, FIG. 2: Pu..X, FIG. 5; Pi. XI, Fics. 3, &. 
Zoarium consisting of irregularly lobed and greatly compressed 
branches or of wavy true fronds arising from a cylindrical base which 
is doubtless attached by an expansion as in other frondescent species. 
An average frond has a thickness of 4 mm. to 5 mm. and a breadth 
of 20 mm. or more. Surface nearly smooth, often completely so; but 
showing in some specimens subsolid sometimes slightly elevated 
macule of cells somewhat smaller than the average. Zocecia round, 
about 45 to the centimeter and from 0.16 mm to 0.2 mm. in diameter. 
Mesopores numerous, angular, filling all the interstices between the 
zocecia. The surface of some specimens seems to be covered in 
places with a thin pellicle, as in other species of Dekayia. 
Longitudinal sections show that the diaphragms are approximately 
horizontal, fairly crowded in the mature region and considerably more 
numerous in the mesopores, which are constricted at the level of each 
diaphragm. The walls present the peculiar beaded appearance char- 
acteristic of D. Ulrichi. 
Tangential sections near the surface show that the zocecia are ring- 
like in the mature region, with fairly thick walls, The acanthopores 
are fairly abundant, and of two sizes, the smaller somewhat more 
numerous. The ratio of the diameters of the largest and smallest 
acanthopores seen, is about as four to one. 
For comparison I have inserted (PI. IX, fig. 1) a tangential 
section of an ordinary ramose specimen of D. ulrichi¥ from 
the Utica beds at Cincinnati (Dalmanella multisecta zone.) It 
will be seen that the internal characters of the two are identi- 
cal. 
Since this variety of D. ulrichi is truly frondescent it 
eliminates from consideration the first of the differentia en- 
* This torm is associated with Platystrophia laticosta, Plectorthis plica- 
tella, Callopora dalei, &c. ‘ 
+ This specimenis from the collection of Bryozoa in the Yale Museum, 
labeled by Ulrich. 
