21. 



rapidly iiai-rowin^ii," towards the beak; 

 low, rounded fold, broad below, narrow- 

 ing' rapidly towards the beak; fine, low 

 and rounded surface plications and gran- 

 ulose character of the whole extei-ic^r of 

 the shell. 



Found in the Deniissa bed, at Section ~). 



Spirifer (Reticularia) fimbriatis. 

 (Conrad.) (Fio-. 123.) (Pal. X. Y.. Vol. 

 IV., p. 214, PI. XXXIII.) 



Distinguishing CharRcters. — Transvei-se- 

 Iv sub-elliptical outline; hinge line less than 

 rounded cardinal extremities; gibbous and 

 vex valves; i-ounded sinus; well-mai-ked 



Fig. 122. S2)irifer 

 asper. Cardinal and 

 ventral views of a char- 

 acteristic pedicle valve, 

 from the Demissa bed. 

 at Section 5, natural 

 size. (Original.) 



width of shell ; 

 regularly con- 

 fold, abruptly 



Fig. 1S3. Spirifer fitnbriatus. Profile, front, dorsal, and ventral views of a large and 

 well-preserved specimen (from Hall). 



elevated in front, low near the beak ; high and concave pedi- 

 cle area ; few (six to eighteen on each valve) low, rounded, 

 often obscure, plications ; concentric lainellose and imbricat- 

 ing growth lines, studded with elongated tubercles or 

 spines (fimbria'), which in perfect specimens show lateral 

 fringes or spinules. 



