232 



Genus LEIORHYNCHUS. Hall. 



[Ety. : l.i ios, smooth ; rhynchos, beak.] 



(1860: 13th Aim. Rep't X. V. State Cab. Nat. Hist., p. 75. 

 1893: Pal. X. V., Vol. VIII.. Pt. II.. p. 193.) 



Ethynchonelloid shells, with the plications on the median 

 fold and sinus highly developed, but those on the lateral 

 slopes usually slightly developed. Other external features 

 as in Camarotoechia. 



Leiorhynchus multicostus. Hall. (Fig. 142.) (Pal. 

 N. V.. Vol. IV.. p. 358, P1.LVI.) 



Distinguishing Characters.— Ovate outline; length and 

 greatest width nearly equal (except in compressed sped- 



.,* 



Fir;. 142. Leiorhynchus multicostus. Cardinal view of a gibbous specimen: two brach- 

 ial valves of different ages; three pedicle valves, one much distorted (from Hall I. 



mens I ; 1 hree to seven rounded plications in the sinus and on 

 the fold, all bifurcating: obscurely bifurcating lateral plica- 

 tions, which become obsolete near the beak; concentric 

 striae. This species is considered identical with L. Iaura 

 < Billings). 



Found in the upper and lower Moscow shales, at Sections 

 1 to 8, and on Hie Lake Shore (especially abundant in the 

 Schizobolus beds): Lower shales, five feet below, and from 

 Fourteen Feel below the Encrinal limestone down, at Sec- 

 tions 7 and 8, and on the Lake Shore ( often abundant ). 



