2 PROCEEDINGS OF THE NATIONAL, MUSEUM. vol.61. 



The classification of the ovicelled c.yclostomat'ous bryozoa so far as 

 our investigations have gone is expressed in the following table. It 

 will be noted that many frequently cited genera are omitted from this 

 classification. In such cases these genera either show no ovicells or, 

 at least, ovicells have not been found in their genotypes so that they 

 cannot at present be placed in a natural classification. In a future 

 paper we hope to give a complete list of cyclostomatous genera indi- 

 cating the status of each. 



The student is referred to our monograph of 1920 for a discussion 

 of the general structure of the Cyclostomata and a description of 

 the various kinds of tubes, their methods of gemmation, the forms 

 of zoarial growth and the types of ovicells developed. The present 

 paper is supplementary to that work, which should be consulted in 

 connection with it. 



In these studies we employ the same terms of nomenclature as in 

 our Early Tertiary monograph. All of these are self-evident ex- 

 cept two measurement, which should be noted. There are (1) the 

 separation of the tubes or j^eristomes, meaning the distance between 

 two tubes opening at the same height, or, in other words, opposite 

 each other and thus separated by another tube, and (2) the distance 

 between the peristomes, indicating the measurement lengthwise 

 along a single tube. These measurements include both peristomes 

 concerned in the first instance and only the one belonging to the tube 

 measured in the second. 



Order CYCLOSTOMATA Busk. 



Division OVICELLATA. 



Subdivision Parallelata Waters, 1887. 



Family ONCOUSOECIIDAE Canu, 1918. 



*07icoiLSoecia Canu, 1918; Pei^istonioecia Canu and Bassler, 1920; 

 Filisparsa D'Orbigny, 1853. 



Family CRISIIDAE Johnston, 1847. 



Crisia Lamouroux, 1816; Crisidia Milne Edwards, 1838. 



Family MACROECIIDAE Canu, 1918. 



*Macroecia Canu, 1918; *Atractosoecia, new genus. 



Family MECYNOECIIDAE Canu, 1918. 



*Mecynoecia Canu, 1918; *T7igonoecia^ new genus; "^Gardioecia, new 

 genus; Nematifera^ new genus; *Microeda Canu, 1918; *Bra- 

 chysoecia^ new genus; *Bisidmonea D'Orbigny, 1852; Entalo- 

 vhora Lamouroux, 1821 ; Exochoecia Canu and Bassler, 1920. 



