LONSDALE ON EOCENE CORALS FROM N. AMERICA. 



523 



11. TUBULIPORA. 



A single imperfectly preserved specimen of a Tubulipora, pos- 

 sessing characters analogous to those of Lamouroux's Obelia, was 

 noticed on a shell imbedded in the white limestone of Eutaw. It 

 was wholly attached, and consisted of three unequal lobes, which 

 sprung from narrow bands composed of two rows of tubes each, 

 and the bands diverged from a central point. The two larger 

 lobes subdivided at the further extremity, and the surface of all 

 three was occupied by abraded tubular openings, which exhibited 

 a slight tendency to a diverging transverse lineal arrangement. 

 In a genus of so great irregularity of growth these characters were 

 not considered sufficient to justify a specific assignment of the 

 specimen. 



Locality. — Eutaw. 



12. Idmonea maxillaris. (sp. n.) 



Branches forked, oval, thickness considerable ; rows of tubular openings short, 

 alternate, mouths in contact ; no central dividing ridge ; tubuli very long ; re- 

 verse surface semi-oval, traversed by longitudinal lines, connected by minute 

 cross lines. 



This figure of Idmonea maxillaris is so drawn as to represent, not the peculiar 

 feature which suggested the specific name, but the more important characters 

 of the tubular openings, the medial longitudinal groove between the rows, and 

 the great range of the tubes within the branch, exposed in the upper fractured 

 part where the openings are wanting : the figure gives also the striae exhibited 

 on the surface and beneath the thin outer layer. 



Viewed in front, this coral resembled a Maestri cht fossil, consi- 

 dered by Goldfuss as a young condition of Idmonea gradata 

 (Petref. Corrigenda, p. 244. Retepora disticha, p. 29. tab. 9. f. 15. 

 a, b\ but it differed essentially from mature specimens of that 

 species, and from Goldfuss's figures, just cited, in the plan of bi- 

 furcation, as well as in the great length of the tubes and the form 

 of the branches. From Lamouroux's typical species (I. triquetra, 

 Exp. Methodiq. p. 80. tab. 79. f. 13 — 15.), and some tertiary spe- 

 cies of similar form, it was conspicuously distinguished, not merely 

 by the rounded outline of the reverse side, but also by its great 

 thickness. 



The bifurcations occurred at irregular distances, sometimes 

 equalling 3J lines, and without any prominent precursory increase 



