288 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



DESCRIPTION OF PLATE 41 



PAGE 



Lingiilella (Lingtilepis) acuminata (Conrad) 262 



Figs. 1-4. Varying forms of the ventral valve. Fig. 4 is much like 

 that of the type specimen of '" Lingulella pinnaformis 

 Owen." 



5-7. Varying forms of the dorsal valve. 



Figs. 1-7 are copied from the figures illustrating this species on 

 Plate XL, figs, ih-n, respectively, of Monogr. 51 U. S. Geol. Survey, 

 1912 (in press). The specimen represented by figure ih is in the 

 U. S. National Museum, Catalogue No. 52469a ; the specimens rep- 

 resented by figures li-n are in the U. S. National Museum, Cata- 

 logue Nos. 5i878a-f, respectively. 



Lingulella prima (Conrad MS.) Hall 262 



Fig. 8. Fragment of a ventral valve, showing the cast of the area, the 



divided umbonal muscle scar (g), and the pedicle scar (m). 



U. S. National Museum, Catalogue No. 27435c. 



9. Exterior of a ventral valve, showing rather strong undulations 



of growth. U. S. National Museum, Catalogue No. 27435b. 



10. Cast of the interior of a ventral valve, showing the pestle- 



shaped ridge that filled the median groove of the interior 

 of the shell. U. S. National Museum, Catalogue No. 27435a. 



11. Partly exfoliated dorsal valve. U. S. National Museum, Cata- 



logue No. 27435d. 

 The specimens represented are all from locality (77), Upper Cam- 

 brian sandstone, Ausable Chasm, Essex County, New York. 



Figs. 8-1 1 are copied from the figures illustrating this species on 

 Plate XXVII, figs, ib, la, i, and ic, respectively, of Monogr. 51, 

 U. S. Geol. Survey, 1912 (in press). 



Triblidiiim cormitaforme (Walcott) "^^Z 



Fig. 12. (X3-) Side view of a small, rather depressed specimen, 

 showing the profile. U. S. National Museum, Catalogue 

 No. 58548. 

 13 and 13a. (X5) Side and top view of a small specimen having 

 an irregular growth. U. S. National Museum, Catalogue 

 No. 58549. 

 14. (X I-S-) Top view. U. S. National Museum, Catalogue No. 

 58550. 



Pclagiclla mimitissima (Walcott) 266 



Fig. 15. (X6.) Side view of a partly exfoliated specimen. U. S. 

 National Museum, Catalogue No. 58551. 

 16. (X 6.) Side view of a specimen preserving the striated outer 

 surface. U. S. National Museum, Catalogue No. 58552- 



