On the comparative osteology of the passerine bird Arachnothera magna / by R.W. Shufeldt.
- Robert Wilson Shufeldt
- Date:
- 1909
Licence: In copyright
Credit: On the comparative osteology of the passerine bird Arachnothera magna / by R.W. Shufeldt. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![in those bii’cls it i.s better marker! a.s a rule, and carried further V)ackward, havdng tiiesupraoecipital prominence standing between the furrows after the common one separates posteriorly. This character is also a feature of the skull in Acanthorhynchus among the Meliphagidre and probably other honey-sucking species which possess tongues, the thyro-hyals of which curl over on top of the skull and are extensible. Cinnyris chalybeus is another example. In A. magna the frontal region is rather broad between the peripheries of the orbits, and still broader in front of the lacrymals, where the cranio-facial line is quite distinct. The superior mandible seen from above is smooth and the culmen rounded. This part of the skull can be.st be studied on side view. Here it will be noted that it is gently decurved for its entire length, which is just double of that of the rest of the skull. It tapers very gradually to the sharp apex, while its tomia possess clean cutting-edges. The rather lai'ge elliptical external narial apertures open far back just beyond the cranio-facial hinge, or rather line (see Plate), and they have no true bony partition separating them mesially. This is entirely different from what we find in the Humming-birds, where these mandibular narial openings are long and slit-like. They are very large, and occupy a mid-position on the bill in such species as Prosthemadera nor>op.- hollandice, Acanthogenys rvfigularis, and other Meliphagidae, forms with shorter and .stouter mandibles. We find that A. magna has a capacious orbital cavity with its osseous walls fairly entire. The pars plana is large and thick and faintly shows above its union with the lacrymal. Its outer margin, forming a part of the periphery of the orbit, is, like the rest of this margin round to the postfi'ontal, sharp and defined. On its orbital side the pars plana is markedly concave, but convex in front, while below it meets the anterior end of the quadi-ato-jugal bar. The latter is almost of hair-like proportions, very delicate, and straight. This is also the case in other species of the Nectariniidse, some few Meliphagidfe, and in the Trochilidae. Nearly all of these birds have a vacuity of a greater or less size in the interorbital septum, and the openings for nerves on the anterior wall of the brain-case, wdthin the orbit, as those for the first pair, are large, and in A. longirostris merge with the foramen in the interorbital septum. The optic foramen, however, is generally distinct, and in such a .species as Climacteris scandens, and probably its near allies, there exists no deficiency in the orbital septum, while the brain-case above exhibits a very laige opening into the orbit. Owing to the extreme slenderne.ss of the o.sseous structures at the roof of the mouth posteriorl}^, the floor of the orbital cavity is distinctly deficient in bone, and this is the case with all the species in this genus, as well as in some of the related forma. On the lateral aspect of the cranium we find the postfrontal process LJi]](https://iiif.wellcomecollection.org/image/b22426851_0007.jp2/full/800%2C/0/default.jpg)
