SMITH ON THE AGE OF THE TERTIARY BEDS OF THE TAGUS. 421 



of Moiit., but differing in having a small mucronation at the 

 posterior part of each rib. 



TURRITELLA BICARINATA. 



Fig. 25. 



Turrit, testa elongato-turrita, crassa, anfractibus subrotundatis, spiraliter striatis, 

 carinis duabus anticis, validis, postica majori. 



The proportions and number of volutions cannot be given because 

 the specimens are very incomplete. 



TURRITELLA {Pvoto, Dcf.) MUTABILIS. 



Fig. 26. 



Turr. testa elongato-turrita, spiraliter striata ; anfractibus planulatis, postice in- 

 flatis, superioribus carinis duabns vel tribus validis, antica majori. 



Remarkable for the last whorls of full-grown shells being almost 

 free from carinse (J. D. C. S.). 



Loc, P090 do Bispo, near Lisbon (Daniel Sharpe). 



Pleurotoma l^vigata. 



Fig. 28. 



PI. testa fusiformi-turrita, crassiuscula, Isevi, anfractibus 9, planulatis, postice sub- 

 incrassatis, rotundatis, apicem versus minutissime crenulatis ; sinu labii extern! 

 lato, baud alto, canali mediocri. 



A shell which bears but little resemblance to any described species ; 

 it is nearest in general form to PL Borsoni of Basterot, from which it 

 may easily be known by the form of its volutions, which are thickened 

 and rounded at the upper or posterior part. 



Pleurotoma denudata. 



Fig. 29. 



Pleur. testa fusiformi-turrita, spiraliter striata ; anfractibus convexis, postice spi- 

 nosis, antice unicarinatis, carina subgranulata. 



This differs from PL tuberculosa in having but one carina upon the 

 lower or anterior portion of each whorl (J.D.C.S.). 

 Loc. P090 do Bispo, near Lisbon (Daniel Sharpe). 



Cancellaria decussata. 



Fig. 27. 



Cane, testa ovata, acuminata, anfractibus quinque, ultimo decussate ; sutur^ 

 canaliculata, labii externi margine incrassato. Long. 0*7, lat. 0*5 poll. 



Casts of the inside alone of this pretty little Cancellaria have been 

 fomid ; they resemble C. elegans in general form, but are much more 

 coarsely decussated. It appears to be distinguishable from C. buc- 

 cinula, Lam., by its much more delicate longitudinal ribs. 



Nassa Pusio. 

 Fig. 30. 



Nassa testa parva, ovato-acuminata, anfractibus senis, rotundatis, versus apicem 

 costato-rugosis, dorso Isevigato ; ultimi anfractus lateribus anticeque concentrice 



