384 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
see two lateral primitive areas. The lateral avicularia are rarely wanting (fig. 2) : 
we have observed (fig. 4) an inexplicable case of an avicularian monstrosity. The 
zooecia apparently never have spines; however, our figure 3 presents some traces 
of them. 
Affinities.- — This species differs from HippomeneUa angustaedes and from Hip- 
pomenella transversata in its aperture exteriorly semilunar (and not elliptical) 
with mucronoid convexity. 
It differs from HippomeneUa rotula , from HippomeneUa capitimortis. and 
from HippomeneUa oostidata in the extremely irregular punctations of its ovicell. 
It differs from all other HippomeneUae in its bilamellar zoarium. 
Occurrence. — Middle Jacksonian: Rich Hill, 5-f miles south of Knoxville, 
Georgia (very common) ; 34 miles south of Perry, Georgia (common) ; 18 miles west 
of Wrightsville, Georgia (rare) ; 17 miles northeast of Hawkinsville, Georgia (com- 
mon) ; 31 miles north of Grovania, Georgia (common) ; Twiggs County, Georgia 
(several localities) ; 12 miles southeast of Marshallville, Georgia (common) ; near 
Lenuds FeriT’, South Carolina (rare) ; Baldock, Barnwell County, South Carolina 
(rare) ; Eutaw Springs, South Carolina (common). 
Jacksonian (Zeuglodon bed) : Suck Creek, Clarke County, Mississippi (rare) ; 
Shubuta, Mississippi (very rare). 
Cotypes. — Cat. Nos. 64080-64082, U.S.N.M. 
HXPPOMENELLA CAPITIMORTIS, new species. 
Plate 85, figs. 17, 18. 
Description. — The zoarium is free, lamellar, formed of two lamellae, back 
to back, and inseparable. The zooecia are large, elongated, elliptical, or oval; the 
frontal is convex, smooth, garnished laterally with a double row of numerous 
areolae. The orbicular aperture (in the interior) is exteriorly formed of a semi- 
lunar anter and of a very convex and mucronoid poster. The ovicell is hyper- 
stomial, embedded in the distal zooecia; the two lateral areas are perforated by a 
very large pore in part occupied by a denticle shaped like the head of a lance. 
The avicularia are absent or very small. 
Measurements. — Aperture [ A«=0.20 mm. „ . j Z s = 0 . 7 0-0 . 9 0 min . 
(exterior) [Zi=0.15-0.18 mm. J °° eCia Us=0.45-0.55 mm. 
Variations. — The rows of areolae are often three in number; on certain parts 
of the zooecia they have thus the aspect of tremopores. The small avicularia 
develop in the place of an areola; they are placed at a distance from the aperture; 
they have a pivot and there is only one to each zooecium. The ovicell is very 
characteristic; it gives the zooecium the vague aspect of a death's head. We are 
absolutely ignorant of the physiologic use of the large perforations and of the little 
tongue in the form of a head of a lance which they contain. 
Affinities. — This species much resembles HippomeneUa semilevis Reuss, 1869, of 
the Priabonian. It differs from it in the presence of the little tongue in the pores 
