DESCRIPTIONS OF SPECIES. 



CEPHALOPODA. 



Belemnites. (Sp. undt.) 



Plate I., tigs, la,, Ih. and Ic. 



Fig. 1. 

 Fig. l.—Belemnitcs, species. Outlines of a longitudinal section of the best specimen 

 collected. Tlie position of the apical groove is seen at a, and indications of what 

 is supposed to have been the siphuncle, may be traced at b. The restoration of 

 the point is purely hjqjothetical. 



Three moi-e or less frai>;mentaiy specimens of a Belcmnite of medium 

 size, which collectively show many of the characters of the guard and 

 phragmocone. As each of these exhibits some peculiarities which are not 

 seen m either of the others, it will be best to describe them separatel}-. 



Xo. 1 is a portion near tlie anterior (or thickest) end of the guard, 

 about an inch and a half in length, and partly imbedded in shale. The 

 specimen is liroken transversely below and obliquely above, so as to give 

 two natural sections at different angles. The outline of the transverse 

 section is ovatel}' orbicular, the sides being disitinctly compi-essed. The 

 lateral diameter is nearly one-sixth less than the dorso-ventral ; the 

 measurements beins; about five and a half bv six and a half lines. The 



