256 



SCHIZODUS APPRES- 



srs. (Conrad.) (Fig. 

 172A.) (Pal. N. V.. 

 Vol. V.. Pt. I., p. 449, 

 PL LXXV.) 



Distinguishing Char- 

 a cters— Sub-r h o m - 

 boidal-ovate outline; 

 length greater than 

 height : short cardinal 

 line; obliquely trun- 

 cate posterior extremity; sub-angular umbonal slope; fine 

 concentric stri.e. 



Found in the Hamilton group of Eighteen Mile Creek. 

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



Fig. 172A. Schizodus appressua 

 both valves conjoined (from Halli. 



Specimen with 



Genus PALjEONEILO. Hall. 



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



(1870 : Preliminary Notice Lamellibranclriata, 2, p. 6. I 



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

 versely ovate or sub-elliptical 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. 



I'al.lonlilo coxstrkta. (Conrad.) (Fig. 173.) (Pal. 

 X. V.. Vol. V., Pt. I., p. :::::i. Pis. XLVIII., LI. I 



Distinguishing Characters.— ( loustricted and projecting 

 posterior end; ovate-cuneate outline; abruptly declining 



> 



Fig. 178. Palceoneilo constricta. Two right valves and one left valve, showing varia- 

 tion from Hall i. 



