BRYOZOA. 171 
Fscharopora.] 
EscHAROPORA CONFLUENS nN, sp. 
PLATE XIII, FIGS. 1-12. 
Zoarium branching, the smallest seen less than 25 mm. high, with the branches 
averaging about 2.5 mm. in width; the largest fragments indicate a hight of from 
80 to 120 mm., and in these the width of the branches varies from 4to8 mm. The 
two surfaces of the branches are generally obtusely ridge-shaped, and in the largest a 
row of monticules, or simply clusters of large cells, occurs on the summit of the 
ridge. Edges thin and sharp, commonly with a coarsely striated or pitted narrow 
border. Through all stages, though less distinct in the oldest, the zocecial apertures 
are narrow and appear to be drawn out at the ends so as to connect by means of a 
narrow channel. This confluent character of the zocecial apertures is better shown 
and more regular in the central rows, where they are also_narrower and on the 
whole considerably smaller than towardthe margins. (See fig. 5.) In the central 
rows, ten in 5 mm. lengthwise ; eighteen or nineteen in 5 mm. diagonally, and five 
and one-half in 1 mm., and ten in 2 mm. transversely ; of longitudinal rows there 
are nineteen or twenty in 2 mm. 
Tangential sections show that the base of the zowcia, excepting those in the mar- 
ginal rows, is bounded by very thin, straight, longitudinal walls, and equally thin 
transverse partitions. This portion of the zocecium therefore may be described as 
a parallelogram, with the length and breadth respectively as four is to one. At 
about the middle of the hight of the primitive cell its sides have spread a little and 
the ends contracted in a corresponding degree. Just as the posterior half is about 
to be roofed over two projections from the side walls, at a points a little behind the 
middle, gradually converge until they meet and thereby cut off and enclose the ellip- 
tical primitive aperture. In the succeeding stages the principal change is a reduc- 
tion in the size of the apertures, caused by an internal deposit. These stages are all 
shown in figs. 6, 7 and.8, but to insure a trustworthy idea of the internal structure 
of the species, they should be studied in connection with figs. 10 and 11. 
Compared with associated Bryozoa, the next described F. (2) limitaris only will 
be found difficult to distinguish. This, however, is due chiefly to the imperfect pre- 
servation of the surface of most specimens. Good examples of the latter are quickly 
distinguished by the different character of the longitudinal interspaces, these being 
occupied by one elongated pit or two smaller ones. 
The zoarium of E. subrecta is always strictly of the simple type, and never 
branches except under abnormal conditions. 
Specimens of this and the following species were catalogued by me in 1886 as 
Ptilodictya ramosa Ulrich (now Escharopora ramosa).* Comparison with the Kentucky 
*Pourteenth Ann. Rep. Geol. Nat. Hist. Surv, Minn., p. 102. 
