392 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
Affinities . — The zooecia with a small mucro resemble Hippomenella ligulata , 
but the present species differs in its wider zooecia (lz= 0.50 and not 0.44 mm.), in the 
presence of three rows of areolae and in the occurrence of a single avicularium. 
Occurrence. — Middle Jacksonian: Wilmington, North Carolina (rare) ; Eutaw 
Springs, South Carolina (rare). 
Cotypes. — Cat. No. 64090, U.S.N.M. 
HIPPOMENELLA CRASSICOLLIS, new species. 
Plate 51, figs. 14-19. 
Description. — The zoarium incrusts bryozoa or shells. The zooecia are little 
distinct, elongated ; the frontal is convex, surrounded with a double row of areolae, 
covered by a very thick and finely granulated pleurocyst. The aperture is semi- 
elliptical in the interior, with two carclelles placed very low; on the exterior it is 
surrounded with a peristome, salient, very thick , supporting two to six large distal 
spines. The ovicell is globular, salient, hyperstomial, embedded in the distal zooecia 
and ornamented with large radial costules. On the frontal there are two or three 
small triangular avicularia with pivots. 
M easurements. — Aperture 
j/m=0.18 mm. 
(7&=0.12 mm. 
Zooecia 
\Lz— 0.60 mm. 
(72=0. 50 mm. 
Variations. — The variable aspect of this species depends on the active intensity 
of the pleurocystal calcification, which may be found shown in figures 16-19. The 
small avicularia are irregularly placed (fig. 19) ; nevertheless they may be sym- 
metrical (fig. 16) ; they are elongated in proportion to the deposition of the pleu- 
rocyst with the result that they are always salient. The large costules of the 
ovicell are placed above the two lateral areas, sometimes perforated. 
Occurrence. — Upper Jacksonian (Ocala limestone) : Alachua, Florida (rare). 
Yicksburgian (Byram marl) : One-fourth mile west of Woodward, Wayne 
County, Mississippi (very rare). 
Yicksburgian (Marianna limestone) : Near Claiborne. Monroe County, Alabama 
(rare) . 
Cotypes . — Cat. Nos. 64091-64093, U.S.N.M. 
KEY TO SPECIES OF HIPPOMENELLA. 
1 Zoarium bilamellar 
Zoarium unilamellar' 
Zoarium incrusting 
( Orifice elliptical, spines 
‘(Orifice nouelliptical exteriorly, few or no spines 
(Very small, transverse, lateral avicularia,-, 
1 1 1 Beak of the large avicularia turned toward the bottom 
Ovicell with two large pores with a small tongue 
Ovicell with large ribs and large pores 
^‘) Ovicell with small, irregular pores 
Ovicell with radial costules and two large pores 
2 . 
5. 
. 10 . 
3. 
.4. 
JI. transversata. 
H. angustaedes. 
II. capitimortis. 
.11. rotula. 
-I/, incondite. 
H. costulata. 
