Pl-ATE (i. 



VliiS. 1-4. (SiiiJiijiutcs Icriiiiitiiiii, now si)c<-ics (p. .",(11). 



1. The iucrustiii!; Zdiirium. X 20, presciitiiiij; the iisiimI aspprt oT Ihr sjieeies. 



2. Another zoMriiiui, X li(i. in whiih tlie gyumocyst is quite sniiiU. 



3. A third specimou, X I'O. with tlie i:ymnoc.v.st wantnig. Tlie spiranien is well slmwn en 



this example. 



4. The ahraded surface of several znoeeia. X 20, showiu!; the pair of lateral dietellae 



and the sinirle distal one. 

 Jlidwayan (Clayton limestone) : ] mile west of Fort (Jaines, (ie<iri;ia. 

 Cat. No. C3S1G. U.S.N.M. 

 Flos. D-6. Acmijoiu trita, new species (!>. :!1S). 



5. Two fragments, natural size, of the free, cylindrical zoarium. 



6. Surface, X 20, showing the indistinct zooecia, the ascopore and the tubules of the 



tremoeyst forming the frontal. 

 Midwayan (Cla.vton limestone) : 1 mite west of Fort O.-iines, Ceiirgia. 

 Cat. No. 63817, r.S.N.M. 

 I'lflS. 7-12. (InstmiulUi rcntriroxfi Canu and P.assler, 1917 (p. 320». 



7. A group of fragments of the free cylindrical zoarium. natural size. 



8. A fragment, X 2(1. showing a small peristomial avicularium. 



9. A bifurcated zoarium. X 20. 



10. An example, X 2(l, in which the large swollen zooecia. lar.ge ascopore ,-ind the lateral 

 areolae are well shown. 

 11,12. Longitudinal section through a ziKiecium without ovicell, X 32, (fig, 12) and through 

 one with ovicell (fig, 11). 

 ai>, apertura : ».st. ascopore: al, olocyst: or, ovicell: /;/, peristome: /;/, suppmi ; p/c, 



])cristomiee: ~, zooecinni. 

 Midwayan (Clayton limestone) : .Mabelvale, near Little Rock, Arkansas. 

 Cat. No. 625S9. U.S.N.M. 

 Figs. 13-15. Pachythcva stiixita. new species (p. 322). 



13. Three fragments of the free cyliudrical zoarium, natural size. 



14. A bifurcated fragment, X 20. showing the prominent peristome with avicnlari.i, the 



smooth frontal and the deepl.v imbedded ascopore. 



15. A broader zoarium, X 20, exhibiting several large triangular avicularian zooecia. 

 Midwayan (Clayton limestone) : Luverne, Crenshaw County, Alabama, 



Cat. No. C.3S19, U.S.N.M. 

 Fios. lf)-20. Beisscliiia forntn. new sjiecies (p. 322). 



10. Two examples of the free. bifolFate zoarium. natural size. 



17. Surface, X 20, illustrating the aspect of the large frontal pores and the ascopore. 



18. Another surface, X 20. with two avicularian zooecia. 



19. Interior of the zooecia, X 20. 



20. Tangential thin section, X 100. passing through the olocyst and slmwing (luincunx 



arrangement of the elements. 

 Midwayan (Clayton limestone): Mabelvale. near Little Rock, Arkansas. 

 Cat. No. 03S;2O. U.S.N.M. 



