390 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
It differs from the other incrusting species in the entire absence of oral mucro. 
Occurrence. — Lower Jacksonian (Moodys marl) : Jackson, Mississippi (com- 
mon). 
Middle Jacksonian: Eighteen miles w T est of Wrightsville, Georgia (very rare) ; 
Rich Hill, 5J miles southeast of Knoxville, Georgia (rare) ; one-half mile south- 
east of Georgia Kaolin Co. Mine, Twiggs County, Georgia (rare). 
Cotypes. — Cat. No. 64086, U.S.N.M. 
HIPPOMENELLA LIGUEATA, new species. 
Plate 51, figs. 6-9. 
Description. — The zoarium incrusts bryozoa, Orbitoides, or creeps over algae. 
The zooecia are short, distinct, oval ; the frontal is very convex, smooth, surrounded 
by a double row of very small triangular areolae separated by some small inter- 
areolar costules. The aperture is somewhat elongated, semielliptical; a mucro 
strap shaped , very salient, oblique or erect, hides the aperture more or less; the 
peristome is ornamented with six large distal spines. The ovicell is globular, 
salient, imbedded in the distal zooecia, elongated, with two very large lateral areas. 
The two avicularia are placed below the aperture, they are of the same size and 
very projecting. 
Measurements. — Aperture j ha— 0.14 mm. „ . rZs=0.60-0.70 mm. 
(exterior) \la= 0.14 mm. ^ 00eCia (Z.3= 0.40-0.44 mm. 
Variations. — Most of the time the zoarium is incrusting, but free zoaria are not 
rare; the lower face is smooth and, according to circumstances, garnished by the 
hydrostatic apophyses (fig. 7). When the mucro is erect the aperture is quite 
visible and without the peristomial thickening the species may be confounded with 
Hippomenella alifera (fig. 6). When it is oblique it hides the aperture more or 
less (fig. 8). In fossilization the small areolae are easily filled up and disappear 
(figs. 6, 8, which are the most habitual aspects) ; but superb specimens with areolae 
are not rare (fig. 9). Then they are triangular and the frontal is covered by very 
fine interareolar costules coalescent at the mucro. 
Figure 9 perhaps represents a variety, for the two avicularia are much smaller 
and adjacent to the aperture. 
Affinities. — This species differs from Ilippomenclla alifera in the salient mucro 
which ornaments its aperture and Avhich in perspective completes the large peri- 
stome. 
It is again in this same mucro that it differs from Hippomenella radicata 
and in the absence of perforated base. 
It differs from Hippomenella tuberosa in its smaller micrometric dimensions 
(Lz= 0.70 and not 0.84 mm.) and in its nontuberose frontal. 
Occurrence. — Middle Jacksonian: Wilmington, North Carolina (common); 
near Lenuds Ferry, South Carolina (common); Eutaw Springs, South Carolina 
(rare). 
Cotypes. — Cat. Nos. 64088, 64089, U.S.N.M. 
