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Show 470 MR. P. E. BEDDARD ON INTERCENTRA IN BIRDS. [May 4, two fair-sized free intercentra followed by two hypocentra. I found exactly the same number of intercentra and hypocentra in Thlnocorus rumicivorus. In Chionls cdba there are 8 free caudal vertebras, the fifth bears a small hypocentrum; then follow two free good-sized intercentra, of which the last is divided by a suture into two parts. Finally, there is a large bifid hypocentrum. Intercentra are also present in the Laridae. In Stercorarius antarcticus there are three small round button-shaped intercentra increasing in size from before backwards, followed by two large bifid hypocentra. E A L L I ; OTIDES. So far as I have been able to ascertain, neither the Ralli (including Hellornls) nor the Otides possess free intercentra. COLUMBcE. The same remark may be made concerning the Pigeons. ACCIPITRES. In Dryotriorchis spectabills there is one free nodule of an intercentrum lying between the first two free caudals; the remaining vertebras have strong hypocentra, which are bifid at the tip. In other Hawks there are no free intercentra, but always hypocentra, which are constantly bifid at the tip and sometimes chevrons. PSITTACI. I have found no free intercentra in any Parrot, but always a certain number of hypocentra, wdiich may or may not be bifid at the tip. OPISTHOCOMI. In a skeleton of the Hoatzin there are three free intercentra gradually increasing in size, and two hypocentra following them. GALLI. Intercentra appear to be rare in this group of birds. I found no free intercentra anywhere, and only hypocentra on the last two caudals of Ahurria carunculata \ CUCULI. In no Cuckoo that I have examined have I found auy free intercentra. But in all there are two or three hypocentra on the last free caudals; one or more is usually a chevron-bone, i. e. perforated. 1 In Crax globicera, however (Parker, "On the Osteology of Gallinaceous Birds, &c," Tr. Zool. Soc. v. p. 169), there are two free intercentra (" hypophyses"). |
