ART. 3 NEW SPECIES OF FORAMINIPEEA VAUGHAN" 17 



DISCOCYCLINA PALENQUENSIS, new species 



Plate 4, figure 4; Plate 7, figures 1, 2 



Test thin, undulate or more or less selliform. Diameter as much 

 as 10 mm.; thickness through the center as much as 1 mm.; at the 

 periphery about 0.25 mm.; increase in thickness toward the center 

 very gradual, without the production of a central umbo. Surface 

 nearly smooth, with small papillae, which range from 23^ to 38)U in 

 diameter. 



The embryonic chambers were not observed. 



Equatorial chambers rectangular in horizontal section, in definite 

 annuli; usual radial distances between the annuli are between 30^ and 

 45^1 ; transverse width of the chambers 23/i to SS/j.. Many chambers 

 are virtually square. The radial walls of chambers in adjacent 

 annuli appear to be more frequently in alignment, but this not inva- 

 riably the arrangement. A dark line is persistently present in the 

 annular walls, and a similar line is usually seen in the radial chamber 

 walls. The equatorial layer is very thin, variable in thickness, about 

 7/u at the center, but between 30ai and 60/^ toward the periphery. 



The lateral chambers are very narrow, separated by walls which 

 are usually much thicker than the intervening chamber. The bound- 

 aries of the chambers are not definite, and attempts to determine the 

 number of layers do not yield precise results. The number over the 

 center is between 15 and 22. The chamber ends also are not clearly 

 marked; the length, however, generally exceeds the height. Small 

 pillars with pointed inner ends are present. The size of correspond- 

 ing surface papillae has already been stated, 



Cotypes.—C&t. No. 371013, U.S.N.M. 



Locality and geologic horizon. — Eight and a half kilometers south 

 of Trinidad, Canton of Palenque, State of Chiapas, Mexico, collected 

 by J. B. Burnett. Eocene; information as to the precise horizon not 

 available; probably middle or upper Eocene. 



Notes on the differences between D. palenquensis and D. stephensoni 

 are given after the description of the latter species. 



