.iRT. 14 FOSSIL AND RECENT BRYOZOA CANU AND BASSLER 39 



Affinities. — This species is deprived of avicularia, but in the Costules 

 their presence is not yet considered as of generic importance. For 

 Cretaceous (Campanian) species very similar in aspect and ornament 

 with an apertural arch Lang, 1922, created the genus PTirynopora. 



Occurrence. — Albatross Station D. 2152, 23/^ miles northwest of 

 Habana Light, 387 fms.; coral. 



Holotype. —Cat. No. 7828, U.S.N.M. 



Genus ACANTHOCELLA Canu and Bassler, 1917 



The costules bear a row of very prominent lumen pores and are 

 separated by lacunae of greater or less size. The aperture is semiel- 

 liptical; the ovicell is hyperstomial and closed by the opercular valve 

 which is much chitinized. 



Genotype. — Crihrilina tubulijera Hincks, 1881. 



Range. — Eocene (Jacksonian) — Recent. 



Structure. — We established this genus in 1917 from a study of fos- 

 sil specimens from the Jacksonian of the Carolinas. We badly inter- 

 preted the function of the opercular valve and we now modify the 

 diagnosis in order to make it conform to the new observations made 

 on recent specimens. 



This genus has the same general struct m^e as Mertibraniporella and 

 Crihrilina. The only difference is in the ornamentation of the cos- 

 tules, which appears to us now of very small value, for it does not 

 correspond to an important modification of an essential function of 

 the zooecium. The ornamentation of the frontal depends exclusively 

 on the form of the primitive spines, of simple specific value in Mem- 

 braniporae as in the Flustridae. 



According to our principles of classification, these three genera form 

 really only a single genus for which it is necessary to preserve the 

 name of Crihrilina. 



The known species of this subgenus are as follows: 



AcantTiocella tuhulifera Hincks, 1881, Recent (Austraha). 



AcantJiocella suggerens Waters, 1881, Miocene (Australia). 



AcantJiocella erinacea Canu and Bassler, 1922, Jacksonian (Carolina). 



AcantJiocella clypeata, new species. Recent (Florida). 



ACANTHOCELLA CLYPEATA, new species 



Plate 4, Figures 9, 10; text Figure 5 



Description. — The zoarium encrusts shells. The zooecia are dis- 

 tinct, elliptical, little elongated; the frontal is convex with the form 

 of a shield; the costules, eight or nine in number are arranged trans- 

 versely, separated by large lacunae, rectangular, decreasing in size 

 toward the median zooecial axis; the trabeculae of junction are 

 arranged concentrically around the frontal center; each costule bears 

 three lumen pores of which the most exterior one is very salient and 



