EXPLANATION' OF PLATK LXXXIII, 



PETRdCERKI.I.A Tiri'AXA ( Ciiiirail ), p. 71!-! 



1. Later:'! \-\uw ni a \i;r\ perfect Ni)eoinien from Texas. 



Cluillichl. Texas. I'al. C: II. U. S. .\'al. Mus.. No. 



20.1)1.).!. 



2. Lateral \ii,A\' of a small internal cast, 



ll'i'iii'iiali soiul : near Ci-inct'irds C'inicr. {126''). 



AxciiTRA Ai;uui'TA Conrarl p. 715 



3-4. Lateral views 1 if t\V(",> small, inenmplete internal casts, 



Xaz'i'.siiil: marl: iicai- Craic/ards Corner, ( IJi'i' } . 



AxciiL-R.\ Aki;x.\k]A ( Alurton ) p, 717 



5. Lateral \ lew nf ilie t\pe sp^eimen. 



Xaz'Csiiil: marl. 



Pl'cnellus dexsatus Conrail p, 720 



6. Later.al view nf an inteiaial cast referred to this species. 



Ili'iioiiali .sa:ij : near Ci'aicforjs Con:cr, (/_'6''). 



TiRiaxdi'Sis ? M Ajni; Wlnttlelil p. 799 



/^y. Two Literal \iews rif the t_\'pe specimen. 

 XazwsiiiL' marl: .\a-ocsliilc hills. 



RnSTEI,I.ARl.\ CTKIW WllitfieM p, 72 1 



g, lO-II, T2-13. Lateral \ie\vs nf the three t>])e specimens. 

 Xaz'csial: marl: Crosszeiclcs Creel:. 



TfRIiljXdrsis "■■ EI.E\'.\T.\ Whitfield p, ■jgj 



I4-I5> Two lateral \ieus of ;i ne,irl\ complete internal cast. 

 Xoz'esinl: marl: Miilliea IIill. iioo). 



RoSTi;i.I..\KI.\ la-Stl'oUMIS Wdntlleld |, yjj 



10-17. Two lateral \'iews of the type specimen. 



Xazesiiil: marl: Crosszeieks ereeh. 



1050 



