NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
539 
aperture is buried at the bottom of a peristomie; it is irregular and formed by 
the development of two lateral lips, separated by a pseudorimule. No avicularia. 
Measurements.- — Zooecia 
j Iz= 0.50 mm. 
[Is— 0.25 mm. 
Affinities . — Only the figured specimen has been found; it bears no ovicell. It 
differs from the type of the genus in its smooth and nonporous frontal and in its 
zoarium, which is free and does not incrust algae. 
Occurrence. — Upper Jacksonian (Ocala limestone) : Alachua, Florida (rare). 
Holotype. — Cat. No. 64181, U.S.N.M. 
Family TUBUCELLARIIDAE Busk, 1884. 
Bibliography (Anatomical). — 1907. Waters, Tubucellaria : its Species and Ovieells, Journal 
Linnean Society, London, Zoology, vol. 30, p. 126, pis. 15, 16. — 1909. Levinsen, Morphological 
and systematic studies on the Cheilostomatous Bryozoa, p. 304, pi. 36, figs. 3, 4, 5. 
The zooecia have no spines ; their frontal is formed of long tremocvstal tubules 
surmounting a thin perforated olocyst. The septulae are numerous, scattered, 
and multiporous. The ovicell is vestibular, being formed by a great expansion of 
the peristomie, which is always very long. The frontal bears an ascopore opening 
into the compensation sac. 
Terminology.— The very considerable thickening of the frontal develops a very 
long peristomie , the lower orifice of which is closed by the operculum and forms 
the true apertura / its outer orifice is the peristomice , which is more irregular in 
form. The latter is surrounded by a more or less thickened and salient peristome. 
Exteriorly, the upper part of the zooecia, which corresponds to the peristomie, is the 
peristomiale. 
Anatomical structure. — The zooecia are provided with closely placed pits or 
areas separated by ridges, each surrounding a pore. This disposition is the rule 
when the tremocyst covers a perforated olocyst. These pits or areas are the ex- 
tremities of well developed tubules, as in the family Myriozoumidae. 
The ovicelled zooecia have a particular form like the gonoecia of the Adeonidae ; 
but they have not at all the same structure. The larvae develop in a large expan- 
sion of the peristomie, forming a peristomial ovicell. In its interior, there is at 
first a normal polypide. This disappears by histolysis and a diminutive and very 
vigorous polypide succeeds it. in which the circular canal and the ganglion may be 
observed. This communicates with the opening of the ovicell and is accompanied 
by a voluminous ovary. 
The diaphragm (irisoid) is attached to the operculum and to the wall. 
There is a large number of delicate muscles attached to the compansation sac, 
and the latter communicates with the exterior by the ascopore. 
The zoarium is free, unilamellar, bilamellar, or cylindrical. It is often articu- 
lated and radicellated. The articulated zoarium generally lives among algae, the 
mobility and flexibility of which it must share. 
