ART. 22. CYCLOSTOMATOUS BRYOZOA CANU AND BASSLER. 77 



Genus DESMEPORA Lonsdale, 1850. 



1850. Desmepora Lonsdale, Polyzoa, in Dixon's Geology and Fossils of 

 the Tertiary and Cretaceous formations of Sussex, p. 281. 



The ovicell is limited, little convex, surrounded by a deep, smooth 

 groove, placed laterally between two pinnules. The tubes are long, 

 cylindrical, oriented, with dorsal irregular gemmation, grouped in 

 pinnules, without peristomes. The zoarium is surrounded by a thick, 

 lamellar epitheca, perforated by vacuoles formed by the superior 

 ramifications of the dorsal and frontal nematopores. 



Ge7iotype. — DeS7nepora seryiicyJindrica Roemer, 1840. 



Range. — Cenomanian-Danian. 



The principal species of this genus are Desmepora blackmorei 

 Gregory, 1909 ; D. pinnigera Gregory, 1909 ; D. reussi Gregory, 1909 ; 

 and D. rugosa D'Orbigny, 1850. 



This genus differs from Osmdipora D'Orbigny, 1849, in its widened 

 and noncylindrical tubes which are grouped in pinnules and not in 

 fascicles. 



The transverse section is very deceptive ; it shows small pores 

 toward the dorsal and large pores toward the frontal as in the 

 Idmoneidae. This arrangement still does not indicate the presence 

 of widened tubes for the longitudinal section indicates that they are 

 cylindrical. In reality we can distinguish three zones — first, a thick 

 peripheral zone formed of lamellar tissue; second, a posterior zone 

 of small tubes or nematopores whose superior ramifications form the 

 vacuoles ; third, an anterior zone of large cylindrical tubes. 



In accordance with this, the longitudinal section shows, first, an 

 anterior zone of large cylindrical polypidian tubes, branched at all 

 heights and diverging toward the pinnules ; second, a posterior zone 

 of nematopores, coming from the interior of the zoarium, directed 

 in a contrary direction to the tubes and branching at their extremity 

 into successive vacuoles; third, a peripheral zone of lamellar tissue, 

 perforated by very irregular vacuoles. The vacuoles of the anterior 

 part are also engendered by the nematopores coming from the inte- 

 rior of the zoarium and arranged between the tubes. 



DESMEPORA SEMICYLINDRICA Roemer, 1840. 



Plate 28, figs. 1-7. 



1840. Idmonea semicylindrica Roemer, Die Versteinerungen des nord- 



deutschen Kreidegebirges, p. 20, pi. 5, fig. 21. 

 1909. Desmepora semicylindrica Gregory, Catalogue Fossil Bryozoa in 



British Museum Cretaceous, p. 110, fig. 29. 



Structure. — The lamellar epitheca is very thick especially on the 

 dorsal, as indicated by the transverse section. The tubes are much 



