49 



Tho nportiire is comprossod PuTM'lliptioal. in outline, in tlie speci- 

 men illustf;it(Hl, hy liy. '.I. with ;i rnodorntely deep sinus .-it tlio angu- 

 lar bacli of tlic IkwIv whorl. And tlio slicll substance is thin, which 

 indicates. prohal>ly. a yonnjj; sliell. or. it may lie. the apical end of a 

 mature specimen. 



Fi^. |tl represents a mat ure specimen. It is much cxtendeil upon 

 the hack lit the body whorl and the shell t;i-adually bccdnu's thicker, 

 but the apeilnri' below the beak riMuains in the sann- position that 

 it is in in the specinu'n shown in tig'. 8. The a])ertnre increases its 

 leutitli. and by reason of the lateral ex])iuision of the shell witii the 

 j^'rowth. it retains a compressed sniicllipt ica I outliin'. but aci[uires a 

 deep sharply aneiilar sinus at the back of the sliell. 



The surface is mai'ked by conceufric undulating striie. that lie- 

 come more and moi-c [irououuced toward the aperture. They are 

 not shown in tlu' illustrations. 



T his species is itistinguislied by the compressed angular serrated 

 back of the shell, and by the compressed, subelliptical aperture hay- 

 ing a dee]), angular sinus. 



l'liiiil<-cr(ix ihetis var. fnihsjiiiiosinii, as illustrated in Pal. X. Y., 

 Vol. \'. jiart 2, Plate III. fig. '.'A), has a continuation of the shell, 

 showing the older growth, similar tc) that jireseryed in our specimens 

 of this s])ecies, but the growth is not wliolly upon the back of the 

 shell as it appears to be in this species. There is a great difference 

 in the growth of the slu'll. below the aj)e.\. in different s])ecies, and 

 in all species tin' a^jcrtures must cliange more or less with the 

 growth of the shell. 



Found by Ct. K. (xreene near C'harlestown. Indiana, in the Hamil- 

 ton Group, and now in the collection of Win. F. E. Gurley. 



CLASS CEPHALOPODA. 



SrB(LAss TETRABRANCHIATA. 



Order NAUTILOIDEA. 



Famita- MEL( )N()CER ATID.E. 



REMELECERAS OLAinCEXSE U. sp. 



Pkdc IV, Fi<j. 1 , lateral view ; Fig. 2, dorsal view; Fig. J, ventral 

 view of flic .s-ame fragment. 



Prof. Hyatt founded the genus lieiiieleceras, dedicated to Reinele, 

 an author on Cephalopods, in 1894, in the Proceedings of the Ameri- 

 —1 



