PLATE XI. 



( il VnmiKSMA ERECTUM. 



Page 153. 

 See Plates 12, 13,25, 86 and 87. 

 I. 2. Two opposite valves of the same Individual. Pig. 2 shows the muscular scar and also gives 

 the comparative elevation of the beaks of the two valves. The I • • ft valve of the specimen 

 also shows the pallial line and muscular impression, which are not represented in the 

 figure. 



fig. :i. A more entire left valve, having tl ars lmt little extend«d. 



Fig. t. A right valve having the cardinal angles much produced. 



Hamilton group. Fultonliam, Se?toliarie Co., X. Y. 



Fig. .". A smaller right valve, showing of the oblique lateral teeth. 



Hamilton group. Cazenovia, N. Y. 

 Fig. 6. A right valve, showing a proportionally greater breadth. and moderately extended cardinal 

 expansions. 



Fig. 7. A porti fa large left valve with vei"j large cardinal alations. 



Hamilton group. Madison Co., X. Y. 

 Pig. 8. \ left valve. Another figure of this specimen is given on plate 86, Hy. 6. 



Hamilton gi p. Caaenoma, N. Y 



Fig. '.i, A large left valve with short broad cardinal angles and unusual height. The impression of the 



ligamental area is longitudinallj striate. I. 

 Fig. 10. A left valve with the cardinal angles narrow and unusually extended. This form is the Arinila 

 crueiformis, Cohbad. Ann. Rep. p. 54, 1841. The specimen preserves the pallial line and 

 muscular impression, which are net shewn in the figure. 



