English biologist and paleontologist (1804-1892) best known for interpreting fossils and coining the term 'dinosaur.' ALS, one page both sides, 8 x 9.75, September 2, 1857. Letter ti a colleague, written from the British Museum. In part: "We have the skeleton of Helotarsus ecaudatus: it has 20 vertebrae between the skull & sacrum, the last of which support moveable ribs, & of these 5 articulate with the sternum: there is also a sacral rib which articulates with the sternum, & which supports the homapophysis of a succeeding rib…The furculum is short but wide, the middle of the rib touching & slightly attached to the manubrium sterni. In the Polybius braziliensis the sternum has two posterior notches, instead of perforations: the arch of the furculum is longer or deeper than it is wide. The four last dorsal vertebra are confluent with a continuous heel below, whilst these vertebra remain distinct in Helotarsus. The coracoid is relatively weaker & its sternal end much less expanded than in Helotarsus: the ulna—& the entire wing are relatively shorter than in H-tarsus…The skull is longer & more slender, and especially the beak, which, in H-tarsus offers more aquiline proportions. Moreover, the nostril, which is low down & close to the posterior notch of the maxillary in H-tarsus, is near the upper border of the mandible in Polybius." Here, Owens sketches the two different beaks to show the difference.
He continues: "This difference strikes me as most adverse to any special affinity between the S. American & S. African Vultures in question. I may add that in Helotarsus there are 7 caudal vertebra, the last with the usual expected & compressed vomerine in shape, but they are relatively smaller than in other Vultures." He goes on to list the names of several skeletons described in his "Catalogue of the Comparative Osteology in the Museum of the R'l College of Surgeons." In fine condition, with writing showing through from opposing sides. A lengthy letter with fantastic content on bird skeletons from one of the leading early experts in his field.
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