Plate 5S. 



Figs. 1-10. ilelrocnjptn biicciilciitn Caini ;iiul Bassler, 1017 (p. 451). 



1. Three specimens of the free cylindrical zoarium, natural size. 



2. A branched zoariiim. X 20, showing the apertnra at the base of n deep peristouiie. 



A broken interzooecial swelling is present. 

 o. Zooecia, X 20, .separated by a salient ridge. One oral avicularinm is develojied. 



4. An old zoarium, X 20, with zooecia having thickened peristomes. 



5. A fragment. X 20. in which the rinnde siiirameu is well shown. 



6. Longitudinal section, X 20. exhibiting the wide peristomie and the thick frontal walls. 



7. Transverse section, X 20, ilhistrating thickness of frontal walls. 



8. Portion of a surface X 20, with the ovieell-like swelling (broken). 



9. A surface, X 20, with the ovicell-like protuberance intact. 



10. Interior of zooecia. X 20. The apertura is almost invisible. Tlie internal zooecial 



walls are very thin. 

 Middle Jacksonian (Ca.stle Hayne liniestonel : Wilndngton, North Carcjlina. 

 Cat. No. 6259S. U.S.N.M. 

 Figs. 11-17. Siiiitthia colliiiii. new .siiecies (]'. l.">7i. 



11. Surface of the multilamellar zoarium, X 20. Here the areolae are small and ar- 



ranged in several rows. The lyrula is visible in some zooeci.'^.. The peristome 

 forms a decided collar around the opening. 



12. Another zoarium, X 20. The areolae are large and are often separated by costules. 



The avicularinm is triangular and placed laterally. 



13. Sketch of the avicularimn. 



14. Apertura with lyrula. 



15. Interior of zooecia. X 20. showing the smooth olocyst and the lyrula. 



16. Ovicelled zooecia. X 20. 



17. Basal side of a free fragment growing upon an alga, X 20. 



Middle Jacksonian (Castle Hayne limestone) : Wilmington, North Carolina. 

 Cat. No. 6412.3, U.S.N.M. 



59 



