2 .")(•> 



m^ 



Fig. 173A. Schizodus appressus. Specimen with 



ScHIZODlS AI'l'KKS- 



sus. (Conrad.) (Fig. 

 172A.) (Pal. N. Y., 

 Vol. v., Pt. I., p. 449, 

 PI. LXXV.) 



Distmguisliing Char- 

 acters. — S n b - r h o ni - 

 boidal-ovate outline; 

 length greater than 

 height; short cardinal 

 line; obliquely trun- 



both valves conjoined (from Hall i. 



eate posterior extremity; sab-angular umbonal slope; fine 

 concentric stri;v. 



Found in the Hamilton group of Eighteen Mile Creek. 

 (Coll. Am. Mus. Nat. Hist. New York.) 



Genus PAL.EONEILO. Hall. 



[Ety. : Palaios, ancient; ueilo, a genus.] 

 (ISTO : Preliminary Notice Lamellibrancliiata, 2, p. (i.) 



Nucula-like shells, with equal, inequilateral valves, trans- 

 versely ovate or sub-eUiptical in outline; the posterior end 

 extended, with a more or less well-defined sulcus along the 

 umbonal slope. The cardinal line is arcuate, and the hinge 

 furnished with a row of regular, small, transverse teeth, 

 which change their direction under the beak, or are inter- 

 rupted by several oblique teeth. Ligament external, lodged 

 in a narrow and shallow groove. 



Pal.^oneilo CONSTRICTA. (Courad.) (f^ig. 173.) (Pal. 

 N. Y., Vol. v.. Pt. I., p. 338. Pis. XLVHI., LL ) 



Distinguishing Characters.— Constricted and projecting 

 posterior end; ovate-cuneate outline; abruptly declining- 



Fig. 173. Palceoneilo constricta. Two right valves and one left valve, showing varia- 

 tion (from Hall). 



