352 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



The recent species of this genus are according to Waters, 1904, and Levinsen, 

 1909: 



Arthropoma (Flustra) ccciUi Savigny-Audouin (1812) 1826. 



Arthropoma (HippotJioa) pesanseris Smitt, 1872. 



Arthropoma (Lepralia) circinata MacGillivray, 1868. 



Among the fossil species we may doubtfully cite Arthropoma (Lepralia) speyerl 

 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. 



fAa=0.20mm. . (3=0.85 mm. 



Measurements. Aperture 7 . n/ . Zooecia , nnt . 



( la =0.20 mm. U2=0.25 mm. 



. ,. A 

 (Jviceli 7 



Affinities. This species differs from Arthropoma speyeri Keuss, 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.C&t. No. 64061, 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 jousseaumi Jullien, 1888. Recent. 



Waters, 1904, 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. 



