352 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
The recent species of this genus are according to Waters, 1901, and Levinsen, 
1909: 
Arthropoma ( F lustra ) cecilii Savigny-Audouin (1812) 1826. 
Arthropoma ( Ilippothoa ) pesanseris Smith, 1872. 
Arthropoma ( Lepralia ) circinata MacGillivray, 1868. 
Among the fossil species we may doubtfully cite Arthropoma ( Lepralia ) speyeri 
Reuss, 1865. 
ARTHROPOMA METULA, new species. 
Plate 46, fig. IS. 
Description. — The zoarium is free, bilamellar. The zooecia are elongated, 
distinct, in the form of quills ; the frontal is convex and is a tremocyst with very 
small pores. The aperture is transverse; the proximal border is linear and bears 
a small rectangular rimule. The ovicell is very large, salient, globular, smooth; 
its orifice is very regular and is closed by the operculum itself. The avicularium 
is placed laterally below and close to the aperture; it is elliptical and salient; two 
lateral denticles serve as pivot. 
M easurements . — Aperture | 
Ovicell 
ha = 0.20 mm. 
?«=0.20mm. 
h or =0.30 mm, 
Jov=0A5 mm. 
Zooecia 
| £.3=0.85 mm. 
b 7 .?=0.25 mm. 
Affinities. — This species differs from Arthropoma speyeri Reuss, 1865, in its 
much larger and higher placed avicularium. This latter species is of Tongrian 
age (to be exact, from the Rupelian). It is remarkable to note that this genus 
appears almost simultaneously in Europe and America. The figured specimen is 
the only one which has been found. 
Arthropoma metula differs from the recent Schizoporella acuminata Hincks, 
1881, in its transverse and not straight avicularia and probably in the nature of 
the ovicell. 
Occurrence . — Middle Jacksonian (Castle Hayne limestone) : Wilmington, North 
Carolina (very rare). 
Holotype. — Cat. No. 61061, U.S.N.M. 
Genus PHONICOSIA Jullien, 1888. 
1888. Phonicosia Jullien, Mission scientifique du Cap Horn, vol. 6, Zoology, p. 51. 
Orifice with posterior lip, straight, and bearing an elongated notch at its 
middle, with the extremity cut squarely. (Translation after Jullien.) 
Genotype. — Phonicosia jotisseattmi Jullien, 1888. Recent. 
Waters, 1901, remarked that the genus Phonicosia was described from one 
small dead specimen, without opercula. The published figure does not permit the 
observation of the closing of the ovicell by the operculum, and we therefore leave 
to the genus Phonicosia the limits established by its author. 
