Plate 15 

 Lc piaster ion arclica 



Figure 1. Forma arclica, station 35511, not typical. 



2. Forma beringensis, intermediate with f. arclica, station 3510. 



3. Forma beringensis, station 3293. 



4. Same, station 3291. 



5. Same (type of forma), station 3277. 



27(1 



