478 



LAMELLIBRANCHIA TA. 



[DEX. EDM. 



chemungensis, Conrad, 1842, (Nuculites 

 chemungensis,) Jour. Acad. Nat. Sci., 

 vol. 8, p. 247, and Pal. N. Y., vol. 5, pi. 

 75, figs. 37-40, Chemung Gr. 



cuneus, Hall, 1883, Pal. N. Y., vol. 5, pi. 

 75, figs. 27-30, Waverly Gr. 



FIG. 816. Cytherodon rhorabeus. 



ellipticus, Hall, 1870, (Schizodus ellipti- 



cus,) Prelim. Notice Lam. Shells, p. 96, 



and Pal. N. Y., vol. 5, pi. 75, figs. 13-15, 



Ham. Gr. 

 gregarius, Hall, 1883, Pal. N. Y., vol. 5, pi. 



75, figs. 41-45, Chemung Gr. 

 nasutus, Hall, 1883, Pal. N. Y., vol. 5, pi. 



75, figs. 10-12, Ham. Gr. 

 oblatus, Hall, Pal. N. Y., vol. 5, pi. 75, 



figs. 41-45, Chemung Gr. 

 pan per, Hall, 1883, Pal. N.Y., ' 



vol. 5, pi. 75, figs. 24-26, 



Chemung Gr. 

 (?) placidus, Billings, 1874, 



Pal. Foss., vol. 2, p. 137, 



Up. Sil. 

 quadrangularis, Hall, 1870, 



(Schizodus quadrangu- 



laris,) Prelim. Notice Lam. 



Shells, p. 96, and Pal. 



N. Y., vol. 5, pi. 75, figs. 



31-36, Chemung Gr. 

 rhombeus, Hall, 1843, (Cy- 



pricardia rhombea,) Geo. 



Rep. 4th Dist. N. Y., p. 



291, and Pal. N. Y., vol. 5. 



pi. 75, figs. 19-23, Subcar- 



boniferous. 

 socialis, Billings, 1874, Pal. 



Foss., vol. 2, p. 138, Up. Sil. 

 tumidus, Hall, 1870, ' 



Prelim. Notice Lam. Shells, p. 94, an 



Pal. N. Y., vol. 5, pi. 75, figs. 1-2, Up. 



Held. Gr. 



halli, Winchell, 1863, Proc. Acad. Nat. Sci., 

 p. 11, Marshall Gr. 



ovata, Hall, 1858, (Cardiomorpha ovata,) 

 Geo. Rep. Iowa, p. 522, Kinderhook Gr. 



whitii, Winchell, 1863, Proc. Acad. Nat. 



Sci., p. 11, Marshall Gr. 

 DOLABRA, McCoy, 1844, Syn. Carb. Foss. 

 Ireland, p. 64. [Ety. dolabra, a mattock 

 or pickaxe.] Obliquely ovate, gibbous; 

 left valve larger than the right ; beaks 

 large, obtuse, nearer the anterior than 

 posterior end ; hinge-line straight, 

 shorter than the shell, not crenulated ; 

 a flat, narrow ligamental area the 

 length of the hinge-line, widest between 

 the beaks ; anterior end narrower than 

 the posterior, rounded ; no byssal sinus 

 or furrows; ventral margin slightly 

 convex ; posterior end obliquely trun- 

 cated, slope flattened ; surface smooth 

 or finely striated. 



alpina. Hall, 1858, Geo. Rep. Iowa, p. 716, 

 Coal Meas. 



carinata, see Cypricardites carinatus. 



sterlingensis, see Cypricardites sterling- 

 ensis. 



DEXIOBIA, 

 chell, 

 Proc. 



Win- 



1863, 

 Acad. 



Nat. Sci., p. 10. 

 [Ety. dexios, 

 on the right 

 side ; bia, 



strength.] Ine- 

 quivalve, ine- 

 quilateral, area 

 undefined, 

 right valve 

 very ventri- 



beak incurved forward ; left valve less in- 

 flated ; hinge-line having a thickened 

 cartilage plate, bearing a linear poste- 

 rior groove. Type D. ovata. 



FIG. 818. Ectenodesma birostratuin. 



Dystactella, Hall, 1883, Pal. N. Y., vol. 5, p. 

 4, (Plates and Explanations,) synonym 

 for Clinopistha. 



insularis, see Clinopistha insularis. 

 subnasuta, see Clinppistha subnasuta. 

 telliniformis, see Clinopistha telliniformis. 



ECTENODESMA, Hall, 1883, Pal. N. Y., vol. 5, 

 pt. 1, p. 4. (Plates and Explanations.) 

 [Ety. ektenes, stretched out; desma, a 

 ligament.] Body ovate, oblique ; height 

 greater than length ; both valves more 

 or less convex ; hinge-line longer than 

 the length of the shell ; byssal sinus 

 shallow ; oblique lateral tooth ; liga- 

 mental area narrow, striated; surface 

 rayed ; distinguished from Glyptodeema 

 by having the anterior wing more pro- 

 duced, and both wings more acute at 

 their extremities. Type E. birostratum. 

 birostratum, Hall, 1883, Pal. N. Y., vol.5, 

 pt. 1, p. 242, Chemung Gr. 



EDMONDIA, DeKoninck, 1844, Desc. Anim. 

 Foss., Carb. Belg., p. 66. [Ety. proper 



