252 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



Vicksburgian (Marianna limestone) : Yicksburg, Mississippi (rare in the lower 

 beds). 



Vicksburgian (Red Bluff clay) : Red Bluff, Wayne County, Mississippi (rare). 

 Cotypes.Cat. No. 64256, U.S.N.M. 



KEY TO SPECIES OP LUNULAKIA. 



[ Vibracula in all the interzooecial angles 4 



'| Vibracula only in alternate interzooecial angles (Oligostresium) 2 



(Zoarium hollow, zooecia dimorphic L. contigua 



" \ Zoarium solid 



[ Condyles with fossette; large, oval opesium L. vicksburgensis 



^ \ Condyles without fossette: small semilunar opesia ._. L. claibornica 



J Zoarium hollow, without ribs on inner face__. . . 5 



[ Zoarium solid, with ribs on inner face 6 



Small zooecia (Ls 0.25 mm), tubular, no partitions '. /.. tubifera 



Large zooecia (LeO.50, 0.70 mm.), zoarial partitions L. distans 



I Inner face with perforated ribs 7 



1 j Ribs of inner face not perforated but tuberose __._ S 



Ancestrular zooecia with a partition ; bordered opesium L. ligulata, 



Ancestrular 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 



I Opesium bordered L. jacksoncnsis 



' [ Opesium not bordered 9 



J Small oval opesium (Jw 0.15 mm.) - -L. ovata 



| Large opesium (ho 0.30 mm.) L. grandipora 



Family ASPIDOSTOMIDAE Canu, 1908. 



Bibliography (Anatomical). 1886. JULLIEN. Mission Scientifique du Cap Horn, Bryozoaires 

 vol. 6, p. 77. 18S9. 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 Eschara (Aspidostoma) gigantea 

 Busk, 1854, with the Onychocellidae. In 1889 Waters figured the opercnlum 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 ectocyst. 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'Orbigny of the Cretaceous; finally, he noted the re- 



