Plate 10. 



Figs. 1-3. Acanlhodesia oblonciula I'lrich and Bassler, 1904. (p. 34.) 



1. One of the original types of this incrusting species, X 20. illustrating the prominent intor- 

 zooecial tubercles and the spinose jirocesses (spicules) surrounding the opesium. 



Miocene (Calvert formation); Plum Point, ^laryland. 



2. A specimen, X 20, showing the interzooecial tubercles joined. 

 Miocene (Choptank formation): Pawpaw Point, Maryland. 



3. Another of the original types, X 20, in which there are lumierous spinose processes but with the 

 interzooecial tubercles little developed. 



Miocene (Choptank formation): Governor Run, Maryland. 

 Figs. 4-5. T^racc/Zma pusi'Ha, new species, (p. 35.) 



4. Ancestrular region of the incrusting zoarium, X 20. 



Miocene (Dui)lin marli: Natural Well, 2 miles southwest of Magnolia. North Carolina. 



5. A well-developed zoarium, X 20, illustrating noimal and regenerated zooecia and the small 

 but salient vihracula. 



Pliocene (Caloosahatchee marl): Shell Creek, De Soto County, Florida. 

 Figs. 6-7. Vibracellina sinipler, new species, (p. 35.) 



6. The incrusting zoarium, X 20, showing the ancestiular region. The vibracula are very rare 

 but heterozooecia are present. 



Miocene (Choctawhatchee marl I : Jackson P)luff, Ocklocknee River, 25 miles southwest of Talla- 

 hassee, Florida. 



7. A small zoarium, X 20, showing the calcified ancestrula which engenders five znoecia. 

 Several regenerated zooecia are jiresent. 



Miocene (Duplin marl): Natural Well. 2 miles southwest of Magnolia. N^)rth Cariilina. 

 Fig. 8. Conopeum gerinanum Ulrich and Bassler. 1904. (p. 27.) 



The incrusting type speiimen, X 20, illustrating the interopesial ca\-ities and other character- 

 istics, 



Miocene (Choptank formation i : Dover Bridge, Maryland . 

 Fig. 9. HemisepteUaJilimargo, new spetiea. (p. 71) 



The incrusting type specimen. X 20. The salient rim separating the zooecia and tlie two large 

 lateral as well as the smaller sjiicules of the opesium are evident. 



Miocene (Yorktown formation): York River, Virginia. 

 Fig. 10-14. Memhranipora JliihcUatn Canu, 1904. (p. 20.) 



10. Surface of an outer lamella, )< 20, with the tubercles worn away and the zooecia groujied 

 around a false ancestrula. 



Miocene (Yorktown formation): Yorktown, Virginia. 



11. Portion of a zoarium, X 20, \vith the zooecia separated by interopesial ca\-ities. 



12. Y'oung zooecia, X 20, with thin mural rims. Other zooecia of this same zoarium are normal, 

 tuberose or separated by interopesial ca\'ities. 



13. Zooecia, X 20, with granulose mural rims. 

 Miocene (Yorktown formation): Near Suffolk, Virginia. 



14. Photograph of an inner lamella, X 20, with the tubercles preserved. 

 Miocene (Yorktown formation) Yorktown, Virginia. 



254 



