453 



and the grooves on each side are shallower and much shorter, not extending forward beyond 

 the last four alveoli. The cranium is more convex behind, especially in the vertical direction, 

 than in the D. delphis, and the superoccipital ridge bends forwards towards the rudimental 

 nasal bones. 



Mus. Leverianum. 



2495. The skull of a smaller specimen of Delphinus dubius, vertically and longitudi- 

 nally bisected. 



Number of alveoli : ^^=102. 



Hunterian. 



2496. The greater part of the maxillary, premaxillary and vomerine bones of the 

 Fronted Dolphin {Delphinus frontatus). 



The external alveolar wall has been removed from the whole of the left series of teeth to 

 expose their implanted portion. The alveoli are 20 in number on the right side of the upper 

 jaw : the anterior part of the left maxillary is broken, but sixteen sockets remain, twelve of 

 which contain teeth. 



Hunterian. 



2497. The lower jaw of the Delphinus frontatus. 



Number of alveoli : 22 24. 



Hunterian. 



2498. The mutilated skull, wanting the lower jaw, of the Delphinus frontatus. 



Number of alveoli : 22 21. 



Mv&. Brit. 



2499. The lower jaw of the Delphinus frontatus. 



Number of alveoli : 23 22. 



Mus. Brookes. 



2500. The mutilated cranium of a Dolphin allied to the Delphinus frontatus. 



The maxillary and mandibular arches are wanting, as well as the basioccipital. The ossi- 

 fied tentorium is exposed. 



Hunterian. 



2501. The cranium of a Dolphin allied to the Delphinus frontatus. 



It has been deprived of the chief part of its maxillary portion and of its lower jaw, and a 

 vertical and longitudinal section has been made in the line of the right occipital condyle, 

 displaying the cranial cavity. 



Hunterian. 



