118 



crenated perforation in the middle, but not a continued syphon : the 

 cells are not round, but in the section appear rather concavo-convex. 

 The colour is of a pearly white. 



" May not this be a variety of the N. costatus of superior growth, occa- 

 sioned by a more southern climate ? But whether it is found at present 

 in a recent or living state, we are ignorant." Testae. Brit. Sup. p. 85. 



LETTER X. 



HIPPURITES DALMATIAN AND VERONESE FOSSILS OF A SIMILAR 



APPEARANCE BELEMNITES, OPINIONS RESPECTING SPECIES 



DESCRIBED. 



LXXV. .HippujiiTEs. A straight or conical shell, furnished in- 

 ternally with transverse septa, and with two lateral, longitudinal, 

 obtuse, and converging ridges; the last chamber being closed by an 

 operculum. 



The Baron Picot de la Peirouse first noticed these bodies, <n a tour 

 through that part of the Pyrenees which is in the neighbourhood of 

 Monferrand and Jougragne, in the department of Aude, where they 

 are known to the inhabitants by the name of Horns. He found them 

 chiefly in a loose brown earth, and in the adjoining lime-stone rocks, 

 grouped with a new species of fossil oyster, and various fossil coralline 

 bodies. In consequence of observing that they were concamerated 

 shells, he was induced to consider them as a new species of orthocera- 

 tites, notwithstanding that he discovered that they were furnished with 



