350 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



thread; the frontal is convex, smooth, with the radial nerves visible by transpar- 

 ency. The aperture is small and bears on its proximal border a rather wide trian- 

 gular rimule. Above the aperture there are two small, simple avicularia. 



fAa=0.12mm. . \Lz= 0.65-0.75 mm. 



Measurements. Aperture 7 _,_ Zooecia^ 7 - . . _. 



lZa=0.10mm. us=0.45-0.50mm. 



Affinities. This species differs from Buffonella rhomboidalis in its longer 

 zooecia, in the sajient separating thread, and the presence of two small supraoral 

 avicularia. 



The same characters also differentiate it from Buffonella incisa Reuss, 1874. 



Occurrence. Middle Jacksonian (Castle Hayne limestone) : Wilmington, North 

 Carolina (rare). 



Holotype.Cnt. No. 64053, U.S.N.M. 



BUFFONELLA RHOMBOIDALIS, new species. 



Plate 46, fig. 2. 



Description. The zoarium incrusts bryozoa. The zooecia are distinct, elon- 

 gated rhomboidal, separated by a furrow; the frontal is convex and absolutely 

 smooth. The aperture is small, without peristome; the rimule is large and rectan- 

 gular. 



j, f :'Aa=0.12mm. . |Z2=0.55-0.65 mm. 



Measurements. Aperture i, Zooecia 7 n An n ~ n 



U3=0.40-0.50rnm. 



Affinities. This species resembles Buffonella incisa Reuss, 1874, very much, 

 in its extreme simplicity of structure. It differs from it only in its larger 

 micrometric measurements (Z3=0.55-0.65 mm. instead of 0.36-0.40 mm.). 



Occurrence. Middle Jacksonian (Castle Hayne limestone) : Wilmington, 

 North Carolina (very rare). 



No. 64054, U.S.N.M. . 



BUFFONELLA MICROSTOMA, new species. 

 Plate 46, fig. 3. 



Description.- The zoarium incrusts shells. The zooecia are very small, elon- 

 gated. distinct; the frontal is smooth and convex. The aperture is very small; the 

 rimule is wide and triangular. The ovicell is globular, salient, and smooth; it 

 opens above the aperture by a small slit ; it may be closed by the operculum. 



, |A=0.06mm. . fZs=0.35mm. 



Measurements. Apertures, . . Zooecia{ 7 



U<z=0.06mm. lfe=0.20 mm. 



Affinities. This species differs from Buffonella incisa Reuss, 1874, in its 

 slightly smaller micrometric dimensions and in its. rimule. which is triangular and 

 not rectangular. Moreover, the European fossil sometimes bears a small, lateral 

 ayicularium, which we have not observed on the American specimens. 



