154 



lines; depth at the symphysis 4 lines ; ditto at the medial angle of 

 the dental edge 4 lines ; length of dental edge 4 lines ; anterior 

 division of ditto 1|- line; posterior ditto 2;q:hnes; heel 3| hnes ; 

 exterior flat, marked by horizontal undulating bands on the base, 

 with a few vertical strise near the heel ; two depressions, broad and 

 shallow ; anterior outline abruptly curved upwards to the point. 

 Stratum, great oolite : locality, Stonesfield. 



4. C. curvidens.— -Maxillary 'pliite, right lower JKw : length 1 inch; 

 depth at the symphysis* 4 lines ; ditto at the medial angle of the 

 dental edge 5 lines ; dental edge 7 lines ; anterior division of ditto 

 3 lines ; posterior ditto ditto 4 lines ; heel 3 lines ; exterior convex, 

 curving rapidly inwards to the symphysis ; exposed portion invested 

 with a thick lustrous enamelloid coating, 3 lines in depth at the 

 symphysis; base expanded and closely striated ; one elongated depres- 

 sion near the heel ; anterior division of the dental edge concave, 

 posterior ditto straight. Stratum, great oolite : locality. Stones- 

 field. 



5. C.falcata. — Maxillary plate, left lower jaw: length 1 inch; 

 depth at the symphysis 3-| lines ; ditto at the medial parts of the 

 dental edge 4 lines ; heel 4 lines ; dental edge 6 lines ; tooth elon- 

 gated, falcate, the point curved upwards ; base shallow anteriorly, 

 expanded and traversed by a broad depression near the heel ; ver- 

 tical striae indistinct ; horizontal bands broad and undulate ; cutting 

 edge concave, forming a single curve without any medial angle from 

 the point to the heel. Stratum, great oolite : locality, Stonesfield. 



6. C. emarginata. — Maxillary plate, left lower jaw: length 2 inches 

 5 lines ; depth at the symphysis 1 inch 8 lines ; ditto at the medial 

 angle of the dental edge 1 inch 1 line ; dental edge 1 inch 7 lines ; 

 anterior division 1 inch ; posterior division 7 lines ; heel (mutilated) 

 7 lines ; exterior flat, marked by fine vertical strise ; depression at 

 the heel circular, deep and broad ; dental edge deeply indented in 

 the form of two semicircles ; symphysis straight. Stratum, great 

 oolite : locality, Stonesfield. 



7. C ritgulosa. — Maxillary plate, left lower jaw : length 1 inch ; 

 depth at the symphysis 4 lines ; ditto at the medial angle of the 

 dental edge 3 lines ; dental edge 65 lines ; anterior division 3 lines ; 

 posterior ditto 3^ lines ; heel 3| lines ; exterior rugose ; one strong 

 depression near the heel striated vertically ; anterior division of the 

 dental edge concave ; posterior ditto ditto nearly straight. Inner 

 surface : triturating tubercles placed very obliquely. Stratum, great 

 oolite : locality, Stonesfield. 



8. C. helvetica.; — Maxillary plate, right lower jaw : length 2 inches 

 5 lines ; depth at the symphysis 1 inch 4 lines ; anterior division of 

 the dental edge 1 inch 4 lines ; breadth of ditto 8 lines. This spe- 

 cimen being much mutilated, the measurements are incomplete. 

 It approaches more nearly to C. mantelli than to any other species. 

 Stratum, molasse : locality, CEtmaringen, canton of Argovie. 



9. C. dutetrii. — Maxillary plate, left lower jaw : length 4 inches ; 

 depth at the symphysis 2 inches 2 lines ; breadth of ditto 7 lines ; 

 depth at the medial angle of the dental edge 2 inches 2 lines ; dental 



