The fewness of the characters used in the above definition is chiefly owing to the fact that the Seals and Sea-lions, although they are referable without a doubt to this order, have undergone in their metamorphosis into aquatic animals so many changes that some of the main features in the structure of their terrestrial relatives have been lost. This group will, however, be again characterised. We shall deal at present with the land division of the Carnivora, the CARNIVORA FISSIPEDIA as they are generally termed. The name is of course given to them to distinguish them from the corresponding division of the PINNIPEDIA. In the latter group the feet and hands are modified into "fins"; in the other the fingers and toes are cleft, as with terrestrial beasts generally. {387} SUB-ORDER 1. FISSIPEDIA. [Illustration] FIG. 190.--Under surface of the cranium of a Dog. x 1/2. _apf_, Anterior palatine foramen; _AS_, alisphenoid; _as_, posterior opening of alisphenoid canal; _BO_, basioccipital; _BS_, basisphenoid; _cf_, condylar foramen; _eam_, external auditory meatus; _ExO_, exoccipital; _flm_, _flp_, foramen lacerum medium and posterius; _fm_, foramen magnum; _fo_, foramen ovale; _Fr_, frontal; _fr_, foramen rotundum; _gf_, glenoid fossa; _gp_, post-glenoid process; _Ma_, malar; _Mx_, maxilla; _oc_, occipital condyle; _op_, optic foramen; _Per_, mastoid portion of periotic; _pgf_, post-glenoid foramen; _Pl_, palatine; _PMx_, premaxilla; _pp_, paroccipital process; _ppf_, posterior palatine foramen; _PS_, presphenoid; _Pt_, pterygoid; _sf_, sphenoidal fissure or foramen lacerum anterius; _sm_, stylomastoid foramen; _SO_, supraoccipital; _Sq_, zygomatic process of squamosal; _Ty_, tympanic bulla; _Vo_, vomer. (From Flower's _Osteology_.)