162 
BULLETIN' 125, UNITED STATES NATIONAL MUSEUM. 
concave proximal border; the peristome is thin, little salient, notched, and bears a 
small very inconstant supraoral avicularium. On each side of the apertura there 
are two small straight avicularia, without pivot, the point above. 
Measurements.— Apertura 
ha = 0.06 mm. 
fa. = 0.04 mm. 
Zooecia 
Lz = 0.40 mm. 
Iz = 0.20 mm. 
Affinities. —This species is quite close to Escharipora stellata Smitt, 1872, a 
recent species off the coast of Florida, in the ensemble of its characters. It differs 
from it in the vertical direction of the oral avicularia, in the less low position of the 
latter, and in the much smaller number of frontal perforations. Escharipora 
stellata MacGillivray, a recent species from Australia, is not the species of Smitt, 1872, 
but it is undoubtedly of the same genus. 
We are absolutely ignorant of the hydrostatic system of this group called 
Escharipora by Smitt, 1872. MacGillivray believed that it belonged to the Adeo- 
nidae. Levinsen considered the stellate pores as ascopores. It has seemed to us 
that one of our specimens had a gonoecium with transverse apertura, but it is 
necessary to await more detailed zoological study in order to classify this group of 
species. 
Occurrence.—Lower Miocene (Chipola marl): Chipola River, Calhoun County, 
Florida (rare). 
Cotypes. —Cat. No. 68676, U.S.N.M. 
Genus ANARTHROPORA Smitt, 1867. 
(For description, see Bulletin 106, U. S. National Museum, p. 430.) 
Levinsen classified this genus doubtfully in the Escharellidae, where we also 
placed it in our monograph on the North American Early Tertiary Bryozoa. The 
absence of the ovieell, the nature of the frontal, and the analogy with certain species 
of Adeonellopsis indicate that the genus is better placed in the Adeonidae. 
Family HIPPOPODINIDAE Levinsen, 1909. 
Genus METRARABDOTOS Canu, 1914. 
(For description, see Bulletin 106, U. S. National Museum, p. 533.) 
METRARABDOTOS COLLIGATUM Canu and Bassler, 1919. 
Plate 4, figs. 3-12. 
1919. Metrarabdotos colligation Canu and Bassler, Geology and Paleontology of the West Indies, 
Bryozoa, Publications of the Carnegie Institution of Washington, no. 291, p. 95, pi. 4, 
figs. 3-12. 
Description. —The zoarium is free, bilamellar, attached to algae by a small, 
expanded base and bent upward like a crank; the fronds are large, bifurcated, but 
narrow. The zooecia are distinct, separated by a salient thread, long and narrow; 
the frontal is smooth, convex, surrounded by a line of large areolar pores often 
separated by short costules. The apertura is suborbicular; the peristomice is oval 
with a proximal pseudorimule. There are sometimes two quite inconstant, small, 
