134 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.61. 



SULCOCAVA CRISTATA D'Orbigny, 1854. 



Plate 19, figs. 13-18. 



1853-54. Sulcocava cristata d'Oebigny, Paleontologie frangaise, Terrain 



Cretace, vol. 5, p. 1021, pi. 789, figs. 4-8. 

 1853-54. Sulcocava sulcata d'Orbigny, Paleontologie frangaise. Terrain 



Cretace, vol. 5, p. 1020, pi. 789, figs. 1-3. 

 1853-54. Sulcocava sulcata d'Obbigny, Paleontologie frangaise. Terrain 



Cretace, vol. 5, p. 1022, pi. 789, figs. 9-12. 

 1899. Stdcocava cristata Gkegoky, Catalogue of the Cretaceous Bryozoa 

 in the British Museum, vol. 1, p. 211 (Bibliography only, not figs. 21, 

 22). 

 1899. Sulcocava sulcata Gregory, Catalogue of the Cretaceous Bryozoa 

 in the British Museum, vol. 1, p. 215 (Bibliography). 

 Stnicture. — The peristomes are arranged in transverse and alter- 

 nate rows on the zoarium, but they are never adjacent and do not 

 form fascicles. The longitudinal furrows are quite regular, but they 

 are easily attenuated by weathering or fossilization ; the general 

 aspect is quite variable. 



The transverse section is generally lozenge-shaped. It is necessary 

 to prepare the meridian section parallel to the longer axis and the 

 longitudinal section to the shorter axis. The zoarium is surrounded 

 by a sort of lamellar epitheca. The tubes are quite small at the center. 

 The longitudinal section is quite interesting and complicated. The 

 tubes are funnel-shaped (=club-shaped) ; they are shorter than in 

 Entalophora-. their gemmation is dorsal and occurs in the immediate 

 vicinity of the zoarial axis. The small interzooecial space is large 

 enough to be easily visible in all the sections ; it opens at the exterior by 

 two small pores visible above and below each aperture. Finally very 

 thick lamellar tissue surounds the zoarium and partially fills the inter- 

 zooecial space ; it consolidates the recurved portion of the tubes, but 

 is independent of the latter. Sometimes it is perforated by a vacuole. 

 The lamellar tissue often narrows the aperture and also the peris- 

 tome, which thus becomes totally or partially invisible in sections. 

 The exterior lamella is less dense than the interior lamellae. 



The meridian section shows the tubes with successive constrictions. 

 This feature is due to the arrangement of the tubes in transverse 

 rows and to the compression of the zoarium in a determined direc- 

 tion. There is no basal lamella, and this arrangement of the tubes 

 does not form lozenge-shaped networks. 



The ovicells are extremxcly rare ; we have not been able to dissect a 

 single one of them, so that the position of the genus in the family 

 Ascosoeciidae is not exactly certain; the exterior appearance might 

 be deceiving. 



Historical. — It is quite true that Sulcococava sulcata D'Orbigny 

 1854, must be identical with Sulcocava cristata, as Pergens thought in 

 1889. Gregory's bibliography of 1909 is good, but his determination 



