Heteroprion

(syn. Pachyptila Ϯ Slender-billed Prion P. belcheri) Gr. ἑτερος heteros  different; genus Prion Lesson, 1829, prion; "GENUS - HETEROPRION, NOV.  ...  Type - H. belcheri, sp. n.  ...  I have consequently restricted Pseudoprion to the P. ariel (= P. turtur) group, which I find to differ essentially from the narrow-billed Prions grouped about P. desolatus, and have therefore introduced the above genus to include the medium-billed Prions, and have named as type the thinnest-billed one, H. belcheri, as this shows best the great difference between this group and the P ariel (= P. turtur) group. The species of this genus have the bill shorter and narrower, the wing shorter, and the tarsus shorter than the members of the genus Prion" (Mathews 1912).

Search for more names on the Key to Scientific Names in Ornithology by James A. Jobling.
Recommended citation
Jobling, J. A. (2018). Key to Scientific Names in Ornithology. In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2018). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from www.hbw.com on 11 December 2018).