360 ON THE GENERA XENICUS AND ACANTHIS1TTA. 



of three other species of Albatrosses that I had in the flesh, namely 

 Diomedea exulans, D. brachyura, and Thalassiarche culminata. In all of 

 these I discovered a hallux present, though in a most rudimentary 

 condition, consisting of a single small nodule of bone, which lies altogether 

 underneath the skin, in the fibrous subcutaneous tissues, and only appears 

 externally as a minute pimple-like elevation, with no claw. In Phcebetria 

 there is a minute claw visible externally, whilst internally tivo small bony 

 nodules are discernible, representing undoubtedly the metatarsal element 

 and the hallux, which, as in all other Tubinares, is reduced to a single 

 phalanx. It is difficult at present to say whether the single nodule of 

 the other Albatrosses represents these two elements fused together, or 

 only one of them : in the latter case it is probably the phalanx itself that 

 is wanting *. 



" The discovery of the rudimentary hallux in the Diomedeinae has led 

 . to finding a similar one in some other birds usually considered to be 

 three-toed, namely the Woodpeckers of the genera Pico'ides and Tiya. 

 In these the hallux consists of its normal number of phalanges, of 

 minute size, as is also the metatarsal. The ' great toe ' thus formed 

 lies completely under the skin, and is only discernible on reflecting the 

 integuments carefully, when the chain of minute ossicles, connected to 

 each other and to the tarso-metatarse by fibrous tissue, appears. 



" These facts render it not improbable that a similarly reduced hallux 

 P Z. S. 1882, m ay really exist in many birds commonly described as three-toed. On 

 the other hand, I have been quite unable to detect even a trace of it in 

 some such birds, as e. g. Rhea, Tetrax, and Pelecano'ides. 



P.Z.S. 1882, 64. CONTRIBUTIONS TO THE ANATOMY OF PAS- 



P.5C9. SERINE BIRDS. PART VI. f ON XENICUS AND 



ACANTHISITTA AS TYPES OF A NEW FAMILY 



(XENICIDJS) OF MESOMYODIAN PASSERES FROM 



NEW ZEALAND.J 



A FEW months ago I received, through the kindness of my friend Prof. 

 Jeffery Parker, of the University of Otago, New Zealand, a small col- 

 lection of birds in spirit from that country, which included most of the 

 peculiar forms of Passeres found there. Amongst them were single 

 specimens of Xenicus longipes and Acanthisitta chloris, the examination 

 of which has proved to be of especial interest. 



* Cf. Voyage of H.M.S. ' Challenger : ' Report on the Anatomy of the Petrels, 

 pp. 13, 14. 



t For Part V. see above, p. 357. 



\ Proc. Zool. Soc. 1882, pp. 569-571. Bead June 20, 1882. 



