70 
BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 
One must not confuse the spinous processes or spinules with the spines. Their 
structure is not similar and their physiologic role is absolutely distinct. The spinous 
processes are here only internal apparatus for support, probably intended to limit 
the movements of the hypostege. 
The large retractor muscle of the polypide is inserted in a corner of the zooecium 
as in Onychocella, Odontionella, and Steganoporella. It results in a great dissymme¬ 
try of the opesium especially on its proximal border. 
The known species of this genus are: 
Hemiseptella ( Vincularia) labiata Busk, 1884. 
Hemiseptella ( Vincularia) steganoporoides Goldstein, 1882. 
Hemiseptella ( Thalamoporella ) michaelseni Cal vet, 1904. 
Hemiseptella ( Bijlustra) denticulata Smitt, 1872. 
Hemiseptella ( Membranipora ) tenuis Desor, 1848. 
Hemiseptella ( Membranipora) lacinia Tuomey and Holmes, 1857. 
Hemiseptella ( Membranipora ) minor Canu, 1908 ( M. sulcata, var. minor Canu). 
HEMISEPTELLA LATA Canu and Bassler, 1919. 
Plate 2, fig. 4. 
1919. Hemiseptella lata Canu and Bassler, Geology and Paleontology of the West Indies, Bryozoa 
Publication of the Carnegie Institution of Washington, No. 291, p. 85, pi. 2, fig. 4. 
Description. —The zoarium incrusts fronds of the bryozoan Metrarabdotos. The 
zooecia are distinct, little elongated, wide, sub rectangular; the mural rim is thin. 
The opesium is elliptical or orbicular, never symmetrical; the cryptocyst is short, 
little deep, irregular; the opesiular indentations are represented by two lateral dis¬ 
symmetric concavities and are often separated by a wide and serrate denticle. 
,, i ■ $0 = 0.30 mm. r/ . [7,2 = 0.42 mm. 
Measurements .—Opesia 7 no on Zooecia 7 A on n or> 
r [ io = 0.22-0.30 mm. I te = 0.30-0.32 mm. 
Affinities .—It is always difficult to characterize a species from the study of a 
single specimen. Exteriorly the zooecia have the form of certain zooecia observed 
in Acanihodesia savartii Savigny-Audouin, 1826; it differs from it in its nonsymmetric 
opesium and in two opesiular sinuosities. 
This species differs from Bijlustra savarti Smitt, 1872, which is not perhaps the 
species of Audouin, in the more constant development of its cryptocyst and in the 
nature of its zoarium, which does not incrust algae. The proximal denticle has been 
clearly observed on three zooecia. # 
Occurrence. —Lower Miocene (Bowden horizon): Cercado de Mao, Santo 
Domingo (very rare). 
Holotype. —Cat. No. 68498, U.S.N.M. 
HEMISEPTELLA? LACINIA Tuomey and Holmes, 1857. 
Plate 14, fig. 10. 
1857. Membranipora lacinia Tuomey and Holmes, Pleiocene Fossils of South Carolina, p. 14, pi. 4, 
fig. 10. 
We have been unable to find any specimens corresponding to the figure of 
Membranipora lacinia, which, moreover, is somewhat confusing, although probably 
indicating the genus Hemiseptella. We reproduce the original figure in the hope that 
some future student will rediscover the species. 
Occurrence. —Miocene?: Smith’s, Goose Creek, South Carolina. 
