100 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



2. Horizontal section X 10, showing embryonic chambers and hexagonal 



equatorial chambers, from west side of Gaillard Cut near Las Cas- 

 cadas (U.S.G.S. station 6019a). 



3. Horizontal section showing hexagonal equatorial chambers and irregu- 



larities in the annuli due to repairs of breakage, a X 10 ; b X 20. 

 Same locality as No. 2 above. 



4. Slightly oblique section X 20, showing narrow zone of equatorial cham- 



bers and two broader zones of lateral chambers, the latter with a very 

 evident lack of pillars. Same locality as No. 1 above. 



5. Vertical section at one side of embryonic chambers showing general 



characters of equatorial and lateral chambers X 20. Same locality 

 as No. 1 above. 



6. Vertical section through the embryonic chambers showing the two 



nearly equal chambers with the straight wall dividing the two, X 20. 

 Same locality as No. 1 above. 



Plate 35. 



LepidocycHna chaperi Lemoine and Douville. 



Fig. 1. Exterior view of specimen X 5. Specimen broken. From upper part 

 of Culebra formation, from Panama Railroad, southern switch, Bohio 

 Ridge, in light-colored limy sandstone (U.S.G.S. station 6025). 



2. Exterior view of small, more complete specimen from same locality as 



the preceding, X 5. 



3. Horizontal section showing early chambers of the microspheric form of 



the species, X 20. From west side of Gaillard Cut near Las Cascadas 

 (U.S.G.S. station 6019f). 



Plate 36. 



LepidocycHna chaperi Lemoine and Douville. 



Horizontal section X 10, showing early central chambers and hexagonal 

 chambers of the equatorial region (U.S.G.S. station 6019/). 



Plate 37. 



LepidocycHna vaughani, new species. 



Fig. 1. View of exterior of specimen X 5, with flat periphery and umbonate 

 center, from limy sandstone half a mile south of Mirafiores Station, 

 on wagon road to Panama (station 6255). 



2. Horizontal section of young specimen with regularly hexagonal equa- 



torial chambers X 20 (same locality as No. 1). 



3. Oblique section X 20, with narrow zone of regularly hexagonal equa- 



torial chambers and broader zones of lateral chambers and a straight 

 division wall (same locality as No. 1). 



4. Specimen showing zone of equatorial chambers about peripheral por- 



tion, lateral chambers covering them in the center X 10. From lime- 

 stone in cut of relocated line of Panama Railroad opposite San Pablo 

 and about 4 miles north of Gamboa bridge (station 6673). 



5. Portion of vertical section (slightly oblique) through the embryonic 



chambers, X 20 (same locality as No. 1). 



