466 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Suborder Hexapogona Cartu and Bassler, 1927 



The ancestrula engenders six zooecia. 



The families belonging to this suborder of cheilostomatous bryozoa 

 are the Chaperiidae Jullien, 1888, Conescharellinidae Levinsen, 1909, 

 Mamilloporidae Canu and Bassler, 1927 and doubtfully the Myriozo- 

 umidae Smitt, 1867, and Lekythoporidae MacGillivray, 1882. 



We class here Myriozoum by simple cell analogy but the ancestrula 

 has not yet been published. Of the Lekythoporidae we know only 

 the ancestrula of the genus Actisecosa and we are not certain that the 

 family is a very natural one. 



In the suborder Pentapogona here proposed must be classed all the 

 other known cheilostomatous bryozoa. However, we must confess 

 that in a large number of families the ancestrula is not yet known and 

 that modifications of this classification are always possible. The 

 presence of five zooecia about the ancestrula appears to be the rule 

 in all the species with buried or heaped up zooecia. The erect 

 zooecia belong to the type of Hexapogona. 



Among the fossi! genera we can cite as belonging to this group are 

 Stichopora Hagenow, 1851, DiscoftuxtrelUuia D'Orbigny, 1851, and 

 Hagenowinella Canu, 1900. 



Family CHAPERIIDAE Jullien, 1888 

 Genus CHAPERIA Jullien, 1888 



In 1888, Jullien, in creating this family classed it correctly in his 

 tribe of the Superovicellata. In 1898, Waters introduced it in the 

 group of Membraniporae because of its exterior aspect. We followed 

 the English naturalist in 1920 but in 1923 we showed the necessity of 

 separating Jullien 's genus into two sections according to the escharian 

 or flustrine appearance of the frontal. 



Now that we have been able to study recent specimens we can 

 finally class the genus more naturally. The exterior aspect of the 

 frontal concave or convex does not have great value and must depend 

 upon some special adaptation; moreover we can see on diaper la 

 albispina MacGillivray these two frontal aspects on the same zooe- 

 cium. Furthermore, the operculum in the two groups is identical 

 and constant in its general structure. The observations of Levinsen, 

 1909, are incomplete; the genus Chaperia belongs to the suborder 

 Hexapogona; until the discovery of the larva it will be necessary to 

 maintain the present classification and adopt provisionally the family 

 Chaperiidae, .Jullien. 



