PLATE II. 



Legend. ?. Umbonal scars. j.. PedicK-gro'nve. 



<• Cardinal scans. ,,s. Pedicle-sheafb. 



I Latera scars. ,i, cardinal area. 



h. Centra scai«. cc. Cardinal callosities. 



'■• Umci-ele centrals. pi. Piatfonn. 



z. External scars. .,. Median septum. 



h. Parietal scar. vg. Vascular .sinu.ses. 



cr Urescent. , 



LINGULELLA, Saltkk. 



Page 55. 

 LiNGULELLA CiELATA, Hall. 



Fig. 1. A pedicle-valve, from which the .shell is partially exfoliated ; showing fiWeS 6f' the curved lateral 

 ami Ihe central scars. X 2- I : i '^'"= ^"y*"' 'aiei ai 



Fig-. 2. A pedicle-valve, refaininjr most of the shell; showing- the surface ornamentation a,„l ih.. 



^^loir 'x 2""' ^^^ '""^""'■"'^' ^^'"'""- ^"^"""'^ '"^ «--atio;":m;::Hr (l./l;sS5: 



Pig-. 3. A brachial valve ; showing fhe'central and lateral muscular imiiiessions and a '<-a,.i. .ii,«^i, a i 

 fined scar (z) which, if not adventitious, may he homologous with the ^'x^.nals^si^^i^/,^ 

 cros-s-rt, or the terminal crescent .scai-s in the Trini."rellid.s. x 2. '»■ "(-ai .s in coo(,.«a 



Vig. 4. An incomplete cast of the same valve. X 2. 



Middle Cambrian. Wear Troy, N. Y. 



LiNGULELLA Dawsoni, Matthew. 



Pig. 5. A cast of the interior of the pedicle-valve. X 3. 



St. John group. Portland, New Biiimwhli. 



LiNGULELLA (?) palijformis, Hall. 

 Pig. 6. A view fi-om the dorsal side of both valves in normal juxtaposition ; showing the clevition of the 

 cardinal area m the pedicle-valve, and its pedicle-slit, which by comnreslionl ,?p. f 1 1 



the exfoliated apical portion of the bra<:hial valve. , X 2. t-omp. e.ssion appears through 



Hamilton shales. Shurger's Glen, Cayuga Lake, iV. T. 

 Fig. 7. A pedicle-valve , showing a faint slit along the position of the pedicle-groove. X 3 



Hamilton shales. Pratt's Falln, Oiwndaga amnty, N. T. 

 Pig. 8. A jiedide-valve, which has been compre.ssed along the tilling of the pediele-slit. X 3 



Hamilton shales. S/iurger's Glm, Cayuga Lakr. N. Y. 



LiNGULELLA Stoneana, WiiiUield. 

 (Lingulella aurora, var.. Hall.) 

 Fig. 9. Dorsal \'iew of a specimen. Natural size. 



Fig. 10. The same, enlarged to three diameters : showing the characters of the cardinal -vrea 

 Fig. 11. An^enlai^ge^uent of the surface ; showing the concentric growth-lines crossed by undulating lamel- 



Potsdam sandstone. In thettpper, mriegated magnesian layers. „.nr yTazomanie, Wis. 



LiNGULELLA AUHORA, Hall. 

 Fig. 12. A doi-sal xiew of the specimen ; showing the high cardinal area, and its pediele-groove v M 

 Fig. 13. Another specimen, similarly enlarged. • ^ . • 



Potsdam sandstone. Near Mazomanie, Wucmisin. 



