138 



reticulated, appearing as if covered with fine gauze, 

 circumference of the upper part somewhat constricted 

 (as if a thread had been tightly tied round it) ; colu- 

 mellar margin arcuated, a littie reflected and in the 

 middle of it a flexure or notch; apex rather rounded 

 and slightly umbilicated. 0,30... 0,20. Budleiyh, 

 Salterton, Devon. 



B. CATENATA. Forbes. BULLA C. Mont. p. 215. 

 t. 7.f. 7. D. p. 478. PUNCTATA. variety, F. p. 

 294. Pellucid, white, glossy, closely and finely stria- 

 ted transversely all over, the striae when magnified seem 

 interwoven or formed into links like a chain ; apex ob- 

 tuse with a visible involution ; aperture extremely large, 

 occupying nearly the entire length of the shell ; var. 

 Frosted, less diaphanous, with a more transparent zone 

 taking in eight or ten of the catenae which are more 

 strongly defined ; subumbilicated. 0,10. Devon, rare. 



BULLA. 



Ovate-globose, involute, devoid of columella or pro- 

 jecting spire ; aperture the entire length of the 

 shell, outer lip with an acute edge. 

 B.LIGNARIA. Lin. 1184. Lam. l.D.p. 480. 



Bl. t. 45. /. 8. List. t. 714. /. 71. Knorr. 6. t. 



37- /. 4. Mont. t. 194,5. Pen. 4. p: UG.Mont. 



