ABT. 22. CYCLOSTOMATOUS BRYOZOA CANU AND BASSLER, 106 



Occurrence. — Cretaceous (Coniacian) : Tours and Saint Paterne 

 (Indre-et-Loire), France. 



Cotypes.—C?iTi\x collection and Cat. No. 68953, U.S.N.M. 



Genus CHILOPORA Haime, 1854. 



1854. Chilopora Haime, Description des Bryozoaires fossiles de la for- 

 mation jurassique, Mfmoires de la Societg G^ologique de France, 

 ser. 2. vol. 5, p. 213. 



Leiosoeciidae, in which the ovicell is smooth, convex, very small, 

 opening sometimes by a large oeciopore. The tubes are cylindrical, 

 without peristome, terminated by a salient lip, with triparietal gem- 

 mation, much recurved at their extremity, separated by mesopores. 



GenotyjJe. — Chilopora guernoni Haime, 1854. 



Range. — Bathonian, Santonian. 



Historical. — Haime created this genus in 1854 for a species having 

 the characters of Heteroyora., but in which the peristomes are dis- 

 tinct from the intermediate openings and provided inferiorily with 

 a salient lip. This character is not limited to this genus, for it has' 

 been found in other species. The thin sections prepared from speci- 

 mens of the genotype have permitted us to define the characters of 

 the genus more exactly. 



CHILOPORA GUERNONI Haime, 1854. 



Plate 16, figs. 8-13. 



1854. Chilopora guernoni Haime, Description des Bryozoaires fossiles de 

 la formation jurassique, Memoires de la Soci6t6 Geologique, Prance, 

 ser. 2, vol. 5, p. 213, pi. 10, fig. 5. 



1896. Chilopora guernoni Gkegory, Catalogue of the Jurassic Bryozoa in 

 the British Museum, p. 693. 



Structure. — The fragments which we have found of this species 

 are very irregular and belonged to very fragile fronds. We still 

 are unable to give an exact idea of the zoarial form. The ovicells 

 are small, appearing arranged longitudinally, and terminated some- 

 times by a large orifice, which we are not yet certain is a true oecio- 

 pore. 



On well-preserved specimens the tubes are provided with the lip 

 and the mesopores are distinct and very small. On other specimens 

 the difference is little apparent exteriorly, but it appears clearly in 

 the tangential sections. 



In the longitudinal sections the tubes are short, cylindrical, re- 

 curved at their extremity, with triparietal gemmation, thin at their 

 origin. The median (basal) lamella is little thickened. The meso- 

 pores are short and expanded; their walls are hollow or moniliform. 

 Diaphragms are sometimes present. 



