94 EOCENE AND LOWER OLIGOCENE OOKAL FAUNAS. 



Tkochocyathus LUNULiTiFOKMis (Coiirad). 



PI. VII, fig-8. 2 to 4, and tig. !1. 



1855. TurhhwUa hniiilitiformis Conrad. Troc. Aead. Nat. Sci. Pliila.. Vol. Til. p. 203. 



1895. Trocliocyuthvs li(niiliti/ormis Vauglian. Am. Geol., Vol. XV, p. 22.3. 



189G. Trochocyathus liiniilitiformis Vauglian. Bull. U. S. Geol. Survey No. 142, p. 51. 



Corallum .siibdiscoid; base convex, attached by its central portion; 

 transverse outline circular; costse distinct, granulate, slightly alternating in 

 size, corresponding to all cycles of sej)ta. Septa in four cycles, six systems. 

 Surfaces densely granulate. Pali before all the septa except the last cycle, 

 their surfaces granulate. Calice circular fossa not very deej). Columella 

 fascicular, its upper surface papillate. Diameter, 9.5 mm.; height, 4 mm. 



Localities. — Jacksou, I\Iississippi ; Montgomery, Louisiana. 



Geologic occurrence. — Jacksoniau Stage. 



Conrad's description of this sjjecies was extremely poor, and he pub- 

 lished no figure. Tliere can be no doubt, however, that he meant this form. 



Troohocyathus lunulitiformis var. montgomeriensis var. nov. 



PI. VII, tigs. 5 to 8. 



This variety can be distinguished from the typical forms of Trochocya- 

 tlnis limuUtiformis (1) by having a flatter base; (2) bv being more depressed; 

 and (3) by its costse being- more prominent and more strongly alternated in 

 size. Diameter, 8 mm.: height, 2.5 mm. 



Locality. — Montgomerv, Louisiana. 



Geologic occurrence. JacksOUiaU StagC. 



Types.— United States National Museum. 



The following gives more detail concerning the wall, septa, etc.: There 

 is no epitheca. The wall is formed by the direct fusion of the distal portion 

 of the septa, witliout the intervention of secondar}^ calcification centers (PI. 

 VII, fig. 9). The septa ai-e com])osed of trabecular : slightly above the 

 wall is a line of divergence. The pali seem to possess their own trabecules 

 and centers of calcification, sej^arate from those of the septa. In the septa 

 the courses of the trabecular are indicated Ijy rows of granules, which are 

 at the same time arranged in cm-ves jiarallel to the septal margins. There 

 is the same alternation in position of the rows of granules already noted 

 in Trochon/afhus hyatti. As the trabecuLT? approach the septal margin they 



