478 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



frontal and placed in all directions there is a very large avicularium with small 

 opcsium and of which the mandible is rounded like the beak of a duck. 



. \Ls=Q.2>5 mm. 

 Measurements. Zooecia \ , . _.., 



[73=0.25 mm. 



Affinities. The European type has distinct and marginatecl zooecia ; the large 

 frontal avicularium appears to us as placed nearer the' apertura. These insignifi- 

 cant differences do not permit us to make a distinct species out of our American 

 specimens. 



The presence of the large frontal avicularium differentiates clearly this species 

 from Rhamphostomella simplex and Rham.pliosfomella convexa. 



Occurrence. Middle Jacksonian: Wilmington, North Carolina (rare) ; Eutaw 

 Springs, South Carolina (very rare). 



Geological distribution. Priabonian of the Vicentin (Waters). 



JJolohjpe.Cat. No. 64140, U.S.N.M. 



RHAMPHOSTOMELLA CONVEXA, new species. 



Plate 62, fig. 12. 



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

 tical, a little elongated, separated by a furrow; the frontal is very convex and is 

 formed of a pleurocyst very finely and very irregularly granulated. The peristome 

 is little salient and bears two symmetrical spines ; the peristomice bears an asym- 

 metrical sinus formed by a quite salient oral avicularium with pivot and opening 

 exteriorly ; the aperture is oblique, imbedded, hidden by the oral avicularium. The 

 ovicell is small, salient, placed on the distal zooecium ; it is very widely open above 

 the apertura and faces the avicularium. 



,, . (3=0.35-0.45 mm. 



Measurements. Zooecia \ , 



U3=0.25-0.30mm. 



Affinities. In this species it is absolutely impossible that the operculum could 

 close the ovicell ; it is closed by the ectocyst itself or by a special membrane. We 

 can only form an hypothesis, for we are totally ignorant of the larval system of 

 the Smittinidae in general. 



This species differs from Rhamphostomella simplex in its zooecia distinct and 

 convex, and in its oral avicularium, which opens exteriorly and not in the peri- 

 stomie. 



It differs from Rhamphostomella l>rendolensis Waters, 1891, in the absence of 

 the large frontal avicularium. 



Occurrence. Middle Jacksonian: Rich Hill, Crawford County, Georgia 

 (rare) ; near Lenuds Ferry, South Carolina (rare). 



Upper Jacksonian (Ocala limestone) : Old Factory, H miles above Bain- 

 bridge, Georgia (rare). 



Holotype.Cnt. No. 64141, U.S.N.M. 



