402 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
HIPPOZEUGOSELLA SEXORPINATA, new species. 
Plate 53, figs. 7, 8. 
Description. — The zoarium is free, cylindrical, or foliaceous, formed of six 
longitudinal rows of zooecia. The zooecia are distinct, elongated, elliptical or 
fusiform; the frontal is very convex and formed of a tremocvst with very small 
pores. The aperture is suborbicular, somewhat imbedded; the peristome is wide, 
little salient, interrupted by a small distal tongue. The ovicell is globular, salient, 
hyperstomial, covered with tremopores like the frontal. On the peristome of each 
side of the aperture there are two small tubular avicularia with a pivot, the beak 
of which is turned toward the interior of the aperture. 
Measurements. — Aperture 
) ha— 0.12 mm. 
1 0.10 mm. 
Zooecia 
Lz— 0.85 mm. 
lz— 0.35-0.40 mm. 
Affinities. — In its exterior aspect, its convex zooecia, and the smallness of its 
tremopores, this species much resembles Hippozeugosella. inflata. It differs from it 
in the somewhat larger zooecial dimensions, and especially in the disposition of its 
zoarium, parts of which are occupied by two supplementary rows of zooecia. 
It therefore approaches close to Hippodiplosella vespertilio , but it differs in 
its mode of bifurcation, which is identical with that of the other species of the 
same genus. It may be verified by the examination of the interior of the zooecia. 
Moreover, its ovicell is closed by a special membrane and not by the operculum. 
O ccurrence. — Upper Jacksonian (Ocala limestone) : Alachua, Florida. 
Cotypes.— Cat. No. 64100, U.S.N.M. 
Genus HIPPADENELLA Canu and Bassler, 1917. 
This new genus is based upon Porella ( Flustra ) margaritifera Quoy and 
Gaymard, 1883, and is described on page 497 under the Smittinidae. We believe 
the genus to be more naturally placed under the Hippoporae, and for that reason 
have mentioned it at this point. 
Group 3, PERISTOMELLAE Canu and Bassler, 1917. 
Anatomical 'bibliography . — 1877. Barrois, Recberches sur l’embryologie des Bryozoaires, pi. 8, 
figs. 22, 31. 40. — 1885. Waters, On the use of the avicularian mandible in the determination 
of the Cheilostomatous Bryozoa, Journal of the Royal Microscopical Society, ser. 3, vol. 5, 
pi. 14, fig. 25.- — 188S. Jullien, Mission scientifique du Cap Horn, pi 9, fig. 2. — 1909. Levinsen, 
Morphological and systematic studies on the Cheilostomatous Bryozoa, p. 317, pi. 17. 
The aperture is oblique without lyrula, cardelles, or rimule. The ovicell is 
hyperstomial and embedded in the distal zooecia. It opens above (and nearly 
opposite) the oblique aperture and below the frontal mucro in a locella, where the 
operculum operates. 
The disposition of the ovicell in respect to the operculum is close to that of 
the Smittinidae. Nevertheless the family differs from the Smittinidae in the 
absence of a peristomie. Between the aperture and the orifice of the ovicell there 
is, as it were, a sort of chamber or locella in which the operculum moves and takes 
