jawbone

["Nicholas R. Longrich" <longrich@phoenix.Princeton.EDU>]

        I have a jawbone I'm trying to identify. It's kind of weird. It 
looks like a carnivore to me, but it only has four incisors, as far as I 
can tell- the bone's in pretty good condition, but the only tooth left is 
the canine.
        The canine itself is pretty deep-rooted- the root can be seen 
extending back under the next two teeth. It looks like it has a hollow 
end on the root. 
        There are five sockets past the canine; the last two look like 
they belong to a single tooth with two roots. Although the front of the 
jaw is rather deep and thick, the back of the jaw appears rather 
slender. It's about 6 inches long.  It was collected along the shoreline on 
the Pacific side of Mexico.
        I looked at felines and canines and I've ruled them out. The only 
thing I can think of would be a seal or something, which might explain 
the slenderness of the jaw, but I really don't know anything about seal 
dental formulae. Does anyone off the top of their head know what this is, 
or have a good book to look at? I'm just sort of curious. 
        thanks, 
        nick L.