PLATE LXVI— CoiiUnueil. 

 SpHENOTUS? ARCDATD8. 



Pftgc 400. 

 Fig'. 18. A catst of a right valve, showing the anterior muwiular impression and pieserving the remains of 

 stria' of growth. 



Chenuing group. iVrtir Paiuniia, N. Y. 



SpHKNOTUS FLAVI08. 



Pajre 4(i:l. 

 Figs. 27-39. Left, right ami cardinal views of a speinnuMi wliich hius botMi somewhat compi-es-sed vertically. 

 Waverly group. Licking Co., Oldv. 



Sphenotus valvulus. 



Page 4oa. 

 Fig. 30. A right valve. 



Waverly group. Newark, Ohio. 



Sphenotus yEolus. 



Page 404. m 'K>ii<.i^ti 



Figs. 31-34. A series of right and left valves showing some variety of form and aspect. 



Waverly group. Ohio. 

 Fig. 3.1. A canlinal view of the specimen fig. 33, showing the long ligameiital area. 



Waverly group. Lirkinf/ Co., Ohio. 



SpATIIELLA ITPICA. 

 Page 407. 

 Figs. 36-40. Left and right valves showing vai-iation in form and proportions. 

 Chemung gi"oup. Toinykins and Chemung Co's. JV. T. 



Spathella ventkicosa. 



Page 408. 

 Figs. 41. 42. Two left valves. 



Burlington sandstone. BurlingUm, Iowa. 



Sphenotus akc^fohmis. 



Page 395. 

 See Plates 65, 76. 

 Pig. 43. A left valve, i-eferred with doubt to this species. 



Chemung group. Near Smethport, Pa. 



