SECONDARY AND TERTIARY FORMATIONS OF NORTH AMERICA. 121 



longitudinal rows of cellules, but the cells of the same row appear to be intimately 

 united. 



The vibracular cells are small, rhomboidal, one to each ordinary cellule and each 

 one placed at the point of contact of four of the latter, encroaching on them, trun- 

 cating their angles so as to make them hexagonal. Under surface, Mr. Lea says, 

 " pores below numerous and very minute ;" we have been unable to examine this side 

 on account of the fragile nature of the only two specimens we have seen, both of 

 which are firmly attached to the matrix. 



From the Eocene of Claiborne, Ala. 



This species appears to be the most rare of the four known at the above locality. 

 It can readily be distinguished, even by the naked eye, by its larger size and the an- 

 nular disposition of the cellules, which is more obvious, to the unassisted vision, than 

 the radiating arrangement. The peculiar position of the vibracular (or " special ") 

 pores will distinguish this from all the other described species of discoidal polyzoa. 



L. contigua, Lonsd., Quart. Jour. Geol. Soc. vol. 1, p. 533, figs, a, b, c. 



" Conical, casts of cells cylindrical, short, oblique to the surface, opening round, rows parallel, not alter- 

 nate, divided by thin plates, successive cells connected by foramina ; concave surface broadly ribbed, closely 

 indented; distance between the two surfaces slightly exceeding the depth of layer of cells; a series of shal- 

 low chambers between the rows of cells." 



" This species resembled the last in the character of the cells, the connecting foramina, and the radiating 

 plates ; but it differed in the distance between the surfaces slightly exceeding the range of cells, and in the 

 ribs of the concave cast being densely covered by minute points, sometimes blended together; no filaments 

 similar to those which project from the equivalent portion of Lunulites distans were noticed." 



We have not been able to identify this species among our specimens, and can only 

 add that, from the above description, it appears to belong to the true Lunulites as 

 restricted above. 



"Locality, Wilmington," [North Carolina, Eocene.] 



L. oblonga, Emmons, Geol. Report, N. Carolina, p. 312, figs. 252 and 253. 



" Polypidom small, conical : cells arranged along a straight line from base to margin ; open cells show 

 that they arc nearly quadrangular ; the* closed cells do not show an orifice ; there is a simple film spread 

 over the cells, and the margins are simple and unlike denticulata." 



North Carolina, (Miocene?) 



We only know of this species by the above description and worse figures. 



SEMIESCHARA, d'Orb. 1851. 



Colony in the form of a plate, lamellar, tortuous and occasionally tubular. Cellules 

 only on one side, (the external surface of the tubular form), and on the opposite side 

 we find a germinal plate, such as occurs between the two layers of Eschara. Cellules 

 arranged in lines, sometimes with little regularity ; consisting of two sorts, ordinary 



