122 MONOGRAPH OF THE FOSSIL POLYZOA OF THE 



and accessory. Ordinal cellules same as the common forms of the family ; accessory 

 cellules of a different form from the ordinary ones, sometimes placed at the beginning 

 of a new line, sometimes intercalated with the ordinary form. Ovarian vesicles or 

 ovicells sometimes occur. On the back the colony shows the lines of cellules. 



Differs from Escliara in having the cellules on only one side, from Cellepora in 

 being always free, and from SemiceVeporaria in having but one layer instead of many, 

 as in that genus. 



S. tubulata, n. s., fig. 5. — Colony tubular, fixed by the base, from which arise 

 rounded, dichotomous branches, somewhat flattened at the point where a new branch 

 takes its origin, section at other points nearly circular. Externally surrounded by 

 from eight to twelve rows of cellules, placed in regular quincunx. Young cellules 

 convex, very distinct above, rounded and prominent; older cellules (and slightly worn 

 specimens) not separated by any lines or concavities. Mouth, in perfect young cel- 

 lules, circular and bordered anteriorly by a delicate lip, not elevated above the surface 

 of its own cellule, but a little higher than the surface of the succeeding one ; in old 

 specimens the mouth is a mere perforation in the surface of the colony, sometimes 

 with the surface slightly sloping towards it. Surface of young cellules almost plain, 

 sometimes marked by a few punctations. especially towards the edges. In older cel- 

 lules the surface is profusely punctate. The shape of the cellules is an elongated 

 oval. This is only visible in the very young states. The inferior face of the tube is 

 irregularly striate or finely rugose transversely, and the separation of the cellule is 

 very distinctly marked by impressed lines, which are gradually deepest at the points 

 where the direction changes. 



Besides the external obliteration of the separations of the individual cells, the only 

 change produced by age observed by us was the more distinct punctation of the sur- 

 face. We have noticed all the varieties of age on the same specimen. 



Locality and p>osition. — Claiborne, Ala.? Eocene. 



Explanation of the figures. — Fig. a, colony, natural size. Fig. b, magnified view, 

 showing both exterior and interior. The cellules are about a mean between the 

 youngest and oldest observed. Fig. c, transverse section. Sometimes this is very 

 elliptical, and the two internal surfaces will form almost parallel lines. 



HIPPOTHOA, Lam. 1821. 

 H. irregularis, G. and H., is a Pyripora. 

 H. tuberculum, Lonsd., is a Pyriflustrella. 



CELLEPORA, Fabricius. 1780. 

 (Not Cellepora, Lam., 1801), Cellepora and Discopora (pars) Lam., 1816, Eschara 

 (pars) Gmelin, Escharina and Escharoides, M. Edwards, (not Escharina, Roem., Reuss, 

 Hagen.), Marginaria (pars) Roem., Reuss, Lepralia, Johnston. 



