602 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
Osthimosia evexa Jullien, 1888. 
The known fossil species are: 
Osthimosia tubifera Canu, 1908, Patagonian of Argentina. 
Osthimosia crassatina Canu, 1908, Patagonian of Argentina. 
Osthimosia parvicella Canu, 1908, Patagonian of Argentina. 
OSTHIMOSIA GLOMERATA Gabb and Horn, 1862. 
Plate 74, figs. 12-19. 
1862. Celleporaria glomerata Gabb and Horn, Monograph of the fossil Polyzoa of the Sec- 
ondary and Tertiary formations of North America, Journal Academy of Natural 
Sciences, Philadelphia, ser. 2, vol. 5, p. 134, pi. 19, fig. 15. 
Description. — The zoarium is massive, globular, measuring as much as 2-1 
centimeters in diameter. The superficial zooecia are scattered, distinct, oval, quite 
erect; the frontal is smooth and surrounded by some large areolar pores; it bears 
a median avicularium, with pivot, oval, with the point directed toward the base. 
The apertura is orbicular and is provided with a very wide and rounded rimule. The 
ovicell is large, smooth, transverse, recumbent; its orifice is very large and placed 
above the apertura. The deep zooecia have a reduced frontal ; the apertura and the 
much enlarged avicularium are alone visible. The incomplete zooecia are quite 
numerous and irregular. There are some interzooecial avicularia, small and with- 
out pivot. 
7 i r , . fArt=0.10mm. 
M easurements . — Apertura \ 7 „ . „ 
1 Im= 0.10 mm. 
Variations.— The superficial zooecia are generally quite erect (figs. 15, 17, 19), 
but they are sometimes simply oblique (fig. 16). When the frontal avicularium is 
broken we have then the aspect of the figure given by Gabb and Horn. In reality 
the specimens of Schismopora globosa more often resemble this same figure. The 
American authors cite their specimen as from Vicksburg. In this locality we have 
only discovered the present species. We think, therefore, that our specimens really 
represent the species described by Gabb and Horn, from a specimen which appears, 
moreover, quite mediocre. 
The considerable enlargement of the frontal avicularium in the deep zooecia 
is a useful phenomenon to note, for it occurs quite frequently. 
Specimens of this species are often covered with incomplete zooecia, which do 
not allow serious determinations. Often, in fact, the zoarium of the Cellepores 
dies suddenly without apparent reason before the complete formation of the zooecia. 
In this species, as in all the massive or branched species, there are zooecia of all 
sizes and forms. 
Occurrence. — Lower Jacksonian (Moodys marl) : Jackson, Mississippi (very 
common). 
Middle Jacksonian: Wilmington, North Carolina (common) ; 31 miles south of 
Perry, Georgia (rare). 
Vicksburgian (Byram marl) : Vicksburg, Mississippi (common). 
Plesiotypes. — Cat. No. 61209, U.S.N.M. 
