.liDlKItJlI 



PLATE n. 



■Leget^a. g. 



.K X 



Fig. 



Fig-. 



FigiM 



tJ'.lM 



Fig. 



Fig. 

 Fig. 

 Fig. 



"I 

 li. 

 <*. 

 z. 

 b. 



Cl' 



tlinbonai siiii-s. 

 Cardinal scars. 

 Later;tl scars. 

 Central scars. 

 Cyno'ete xeiiti-als. 

 External scars. 

 Pai-ietal scar. 

 Crescent. 



PfedicK-^i om f!. 

 Pedicle-sTieath. 

 ('ardinal area. 

 Canllnal callosities. 

 Platform. 

 Median septum. 

 Vascular sinuses. 



!'■ 

 ps. 



d. 

 cc. 



pi. 



s. 



vs. 



lO/l.I 



LINGULELLA, Salter. 



I i , . Page. 55. ,■ , / ,m i . , ,- , 

 LiNQULELLA CiELATA, HalUi 



1. A pedicle-valve, from which the shell is jiJirtially exfoliated!';' s'Kd'w'''i^tt'acey '(if" thie 'curved lateral 



'i HTid the central seal's. X 2. " - /Ij-,' l;;ni - hI ,; l . i .i:, I'I .>i ...i'-i 



2.' A pedicle-valve, retaining most of the shell; showing th^' surface ornamentation and the open- 

 ing of the foramen; (a) longitudinal section, showing the elevation of the beak; (b) postenor 

 elevation. X 2- ' -- --i^'h. ■'-■■ - .:-,-.■ Ij-.in .,,:....:-..,■.,,. -.I,;,, r i >: i -i-l 



3. A hi-achial valve ; showing'the central and lateral muscu'lar- iiiljiressidrisj aftd a' 't'^rV' ^ha'i'ply de'- 

 Uned scar (z) which, if not adventitious, may be homologous with the external scairs in Obolella 

 ci-assa, or the terminal crescent scai-s in the Trimerellids. X 2. '■'' '"1 ' m r,j 

 "4.' An incomplete cast of the same valve. X '^^ 

 '•■'■''  ' Middle Cambrian. Rear Troy, N. Y. 



LiNGULELLA DA.WSONI, MlltthCfl'. 

 5. A cast of the interior 13? tlie pedicle-valve. X 3!' 



St. John group. Portkaid, Ifew B}"uii3wick. 



LiNGULELLA (?) B?AX,tFORMIS, HilU. 



Fig. 6. A view from the dorsal side of both valves in noi'mal juxtaposition ; showing the elevation of the 

 cardinal area in the pedicle-valve, and its pedicle-slit, which by compression ajjjiears throuo-h 

 the exfoliated apical portion of the brachial valve. , X 2j , '' 



Hamilton shales. t>hiirger's Glen, Cayuga Lake,^N, Y. 

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

 ,,,i. Hamilton shales. Pratt's FalU, Oiwndaga county, N. Y. . ,..:!;. 



Pig. 8. A pedicle-vahe, which has been comjire-ssed along the tilling of the pedicle-slit. X 3. 

 Hamilton shales. Shurger's Grlen, Cayuga Lake, R. Y. 



LiNGULELLA StoneIsa, Whitfield. 



(lAngulella aurora, var.. Hall.) 

 9. Dorsal vievc of a specimen. Natui'al size. 



10. The same, enlarged to thi-ee diametei's ; showing the chai'actei's of the cardinal area. 



11. An enlargement of the surface ; showing the concentric gi'owth-hnes crossed by undulating lamel- 



illose>fltll'iae>-i 1 -i:!i .. IP !■ ; :;•■: i.- -|- ,j,,i' .  .■; n ; ■ii..,' .-.,1 , . ■■-.,11 ,''.; .^J|■|' 



Potsdam Sandstone. In th^ki/j^per^ variegated inagne'sian layers, near Mmomnnie, Wis. 



LiNGULELLA AURORA, Hall. 

 Fig. 12. A dorsal view of the specimen ; showing the high cardinal area, ami 

 Fig. 13. Another specimen, similarly enlarged. _ i i . 



■il.iiioi. •.,!) i;Miv/..ii- Potsdam saudstoue. Near Mazmnanieil Wuconsin. 



its pedicle-groove. X 3. 



