144 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



nature of its mural rim also are as in Antropora Norman. 1903 ; but species of this 

 genus are provided with avicularia. To be exact, it would be necessary to create a 

 new genus, but as we possess only the single specimen figured, we think it prudent 

 to await for more abundant material. 



Occurrence. Wilcoxian (Bashi formation) : Woods Bluff, Alabama (very 

 rare). 



ffolotype.Cat. No. 63833, U.S.N.M. 



ALDERINA PULCHERRIMA, new species. 

 Plate 29, fig. 1. 



Description. The zoarium is free, imilamellar. creeping over algae. The 

 zooecia are large, elongated, elliptical; the mural rim is broad, concave, smooth, 

 enlarged below. The opesinm is elliptical, elongated, entire. The ovicell is hyper- 

 stomial and never closed by the opercular valve, is globular, very salient, distinct 

 from the mural rim, furrowed in front; it is formed of two calcareous lamellae of 

 which the exterior one is of the same nature as the mural rim. 



Measurements. Onesia 



ho=Q.80 mm. . \Lz=l. l 20 mm. 



7 /->,?/-. Ziooecia , ,, 



fo=0.50 mm. \lz=O.SO mm. 



This very beautiful species has no related form either fossil or living. 

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

 near Lenuds Ferry, South Carolina (very rare). 



Lower Jacksonian (Moodys marl) : Jackson, Mississippi (very rare). 

 Holotype.Czt. No. 63918, U.S.N.M. 



ALDERINA LUNATA, new species. 

 Plate 29, fig. 5. 



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

 rated by a deep, somewhat elongated, oval furrow; the mural rim is very thin 

 distally, somewhat enlarged proximally, granulated. The opesium is elongated, 

 elliptical, or oval, and very finely crenulated. The ovicell is globular, salient, and 

 transverse; the frontal area is in the form of a crescent and granulated like the 

 mural rim. 



Measurements. Opesia 



7(0=0.30-0.32 mm. 7 . } 7,3=0.40-0.50 mm. 



/o=0.22-0.25 mm. ia Uz=0.25-0.30 mm. 



Affinities. This species differs from the recent Alderina imbellis Hincks, 1860, 

 in the less length of its ovicell (0.15 instead of 0.20 mm.) and its frontal area, 

 which is in the form of a crescent instead of being rectangular. These differences 

 are insignificant, for the micrometric measurements are identical, and they occur 

 almost within the possibilities of the habitual variations of a species. If we have 

 created a distinct species it is because Alderina imbellis has never been found 

 fossil, and because such a sudden appearance in the Lower Eocene seems to us too 

 unusual. 



A more closely related species is Alderina irregularis Smitt, 1872, in which the 

 micrometric dimensions are also identical. It differs from it simply in its crescent 



