252 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM, 
Vicksburgian (Marianna limestone) : Vicksburg, Mississippi (rare in the lower 
beds). 
Vicksburgian (Bed Bluff clay) : Eed Bluff, Wayne County, Mississippi (rare). 
Cotypes. — Cat. No. 64256, U.S.N.M. 
KEY TO SPECIES OP LUNULARIA. 
Vibracula in all tlie interzooecial angles 4 
Vibracula only in alternate interzooecial angles (Oligostresium) 2 
Zoarium hollow, zooecia dimorphic L. contigua 
Zoarium solid 3 
Condyles with fossette; large, oval opesium L. viclcsburgensis 
Condyles without fossette; small semilunar opesia L. claibornica 
Zoarium hollow, without ribs on inner face 5 
Zoarium solid, with ribs on inner face 6 
Small zooecia {Lz 0.25 mm .), tubular, no partitions I.. tubifera 
Large zooecia {Lz 0.50, 0.70 mm.), zoarial partitions L. distans 
Inner face with perforated ribs 7 
n x “ — 
0 Ribs of inner face not perforated but tuberose ; S 
Ancestrular zooecia with a partition; bordered opesium 1 L. ligulata. 
Aneestrular zooecia with four pores : L. fenestrata 
Ancestrular zooecia tuberous, cryptocyst larger than the opesium L. verrucosa 
Ancestrular zooecia with a semicircular salient thread L. tintinabula 
Opesium bordered L. jaclcsonensis 
Opesium not bordered ’ 9 
Small oval opesium (ho 0.15 mm.) L. ovata 
Large opesium (ho 0.30 mm.) i L. grandipora 
Family ASPIDOSTOMIDAE Canu, 1908. 
Bibliography ( Anatomical ). — 1886. Jttllien, Mission Scientifique du Cap Horn, Bryozoaires 
vol. 6, p. 77.; — 1889. Waters, Scientific Results Voyage Challenger, Suppl. Rep. 31, p. 28, pi. 1, 
figs. 16-18 ; pi. 3, figs. 20, 21. — 1905. Waters, Bryozoa from near Cap Horn, Journal Linnean 
Society, vol. 29, p. 243 pi. 29,' figs. 1-3. — 1909. Levinsen, Morphological and Systematic Studies 
Cheilostomatus Bryozoa, p. 171. 
The zooecia have a raised margin, often indistinctly or incompletely devel- 
oped. The two opesiules appear as narrow incisions, which join the zooecial 
aperture; the short polypide tube, which is not continued under the cryptocyst 
cover, is in most cases provided with marginal flanges. Avicularia are always pres- 
ent. Ovicells are hyperstomial. 
In 1886 Jullien discovered the relationship of Eschar a ( Aspidostoma ) gigantea 
Busk, 1854, with the Onychocellidae. In. 1889 Waters figured the operculum and 
noted its resemblance to Rhagasostoma Koschinsky, 1885. In 1905 he confirmed the 
fact that the opesiular indentations serve as a passageway for the opercular muscles. 
He established that in Rhagasostoma the operculum is borne by the ectocvst. In 
1909 Levinsen thought that the lateral indentations were opesiules and classified 
the family in the Coilostega tubifer, because he discovered a sort of polypidian tube. 
Moreover, he discovered in Crateropora falcata Levinsen an avicularium analogous 
to that of Eschara antiopa D’Orbignv of the Cretaceous; finally, he noted the re- 
