OSTEOLOGY OF LANIUS LUDOVICIANUS EXCUBITORIDES. 
By R. W. SHUFELDT, M. D., 
Captain, Medical Department, United States Army. 
Mr. Robert Ridgway, in his carefully prepared check-list of North 
American Birds (Bull. No. 21, Nomenclature of N. American Birds, 
chiefly contained in the U.S. Nat. Mus., Washington, D. C.), gives us 
the representatives of Laniide, the species borealis and ludovicianus, 
with the two western varieties of the last, robustus and excubitorides, 
which latter form we have chosen as the subject of this paper to demon- 
strate the peculiarities of the skeleton of these interesting birds. The 
habits of the Shrikes are well known to all ornithologists, so one will not 
be surprised, after a view of Fig. 100, in the plate (where our subject has 
been made, by the aid of the dissecting knife and maceration, to exhibit 
one of the truest indices of his character), to find the large, semi-hawk 
like skull surmounting the remainder of a bony frame-work, that might 
easily be mistaken as belonging to a Thrush or any other Oscine; but 
it is this very characteristic that individualizes these truly passerine- 
raptorial birds. 
In the skull, divested of the lower jaw and hyoid arch in the adult, 
we find that anchylosis of the primoidal segments has been very thorough ; 
outside of the bony parts of the sense capsules—the ossa quadrata and 
the pterygoids are the sole escapers of this notorious feature in avian 
craniology—indeed, we discover in the skull of this species, before it 
has left the nest, that the primitive segments that go to make up the 
group of bones that we described as the occipital vertebra in former 
papers are well advanced towards permanent union, especially about the 
condyle, traces of its formation being extremely difficult of discernment, 
and in the mature bird this hemispherical facet for the atlasis exceedingly 
diminutive, measuring only .5 of a millimeter in diameter. About the 
basi-cranii we find the usual foramina for the exit and entrance of vessels 
and nerves, and note in our examination that the anterior apertures of 
the Eustachian tubes are double, very small, and protected by an osse- 
ous lip from the basi-sphenoid. The foramen magnum is sub-circular 
and of medium size; together with the basi-cranii, it makes an angle with 
the horizontal plane of 25°, the anterior bearing point being the tip of the 
beak, and the two posterior bearing points being the internal facettes 
upon the ossa quadrata. That part of the cranium above, formed by 
the frontals and parietals is very broad and smooth, and quite often 
the sutural traces are easily made out, and in cases where maceration 
is persisted in, the coronal suture may gape; beyond, the interorbital 
region becomes slightly depressed. The pseudo fronto-maxillary articu- 
lation is denoted by a transverse line nearly a centimeter long, and is 
moderately flexible; the superior tips of the lacrymals form its lateral 
boundaries. The superior mandible is made up of the usual bones, it 
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