Complete Fibulae in existing Birds. 363 



during the early life of the embryo. I find in an adult 

 Pandion carolinensis of Prof. O. C. Marsh's collection an 

 entire fibula, but with the distal end of it not in front of the 

 tibia, as in Archseopteryx {Marsh) " (/ Science/ 1885, no. 118, 

 p. 375). In the same journal, under the title of '' A Com- 

 plete Fibula in an Adult living Carinate Bird,'' the present 

 writer took occasion to point out to Dr. Baur in an early 

 succeeding issue (no. 125, p. 516) that Pandion is not the 

 only bird that enjoys the possession of a complete fibula, 

 for that bone is complete also in the leg of the adult Cohjmbus 

 septentrionaJis, and a figure of the skeleton of the right 

 thigh and leg of that species was there given to demon- 

 strate the fact. 



In a few instances, anatomists, after the publication of 

 these notes by Dr. Baur and myself, appeared to avail them- 

 selves of the information afforded to them, and we find that 

 Dr. John Bland Sutton, F.R.C.S., in his excellent work upon 

 'Ligaments, their Nature and Morphology,' states that ''the 

 fibula of birds is usually imperfect, and presents itself as a 

 slender osseous rod attached to the outer side of the tibio- 

 tarsus." Mark, he says " usually," and the Doctor completes 

 his definition by adding, " Its proximal end articulates with 

 the outer condyle of the femur, being received in the fibular 

 fossa ; the distal end gradually thins and fuses with the 

 tibio-tarsus. Although, as a rule, the fibula is shorter in the 

 adult bird than the tibia, yet it may be of the same length, 

 as in some of the Penguins " {op. cit. p. 50, 1887) . 



In one specimen of the extinct Ichthyornis, Marsh found the 

 fibula to be " a slender rod, moderately thickened above, and 

 tapering to a point at the distal end, where its attachment 

 to the tibia appears to have been as slight as in any living 

 bird" (' Odontornithes,' 1884, p. 174). This would seem 

 to imply that Professor Marsh held, at the time he wrote 

 his great work just cited, that there were no existing birds 

 with complete fibulse. 



Claus and Sedgwick were quite positive about it when the 

 * Elementary Text-Book of Zoology ' appeared in 1885 j for, 

 in speaking of the skeleton of the limbs in Aves, on p. 237 



2c 2 



