548 ON THE RUDIMENTARY HALLUX OF BIRDS. [June 20, 
Mr. Sclater also exhibited some Lepidopterous and other Insects 
which had been recently reared at the Insect-House in the Society’s 
Gardens under the care of Mr. A. Thomson. 
The following is a list of the species exhibited :— 
Attacus mylitta. Sciapteron tabaniforme. 
— cynthia. Sesia scoliiformis. 
Samia cecropia. formiciformis. 
—- conopiformis. 
Cricula trifenestrata, —— musciformis. 
spheciformis. 
Deilephila euphorbiz. 
‘Trochilium apiforme. Argynnis paphia. 
melanocephalum. Lyceena iolas. 
Mr. W. A. Forbes exhibited preparations showing the rudimentary 
hallux of several birds commonly described as three-toed, and made 
the following remarks :— 
“Whilst engaged in working out my ‘Report on the Anatomy of 
the Petrels’ for the ‘ Voyage of H.M.S. Challenger,’ I happened 
to come across Dr. Kidder’s note ' on the existence of a rudimentary 
external hallux in Pheebetria fuliginosa, a bird hitherto supposed, 
like other Albatrosses, to lack the hind toe altogether. Finding, on 
an examination of my specimen, his remarks correct, I proceeded to 
examine examples of three other species of Albatrosses that I hadin the 
flesh, namely Diomedea exulans, D. brachyura, and Thalassiarche cul- 
minata. In all of these I discovered a hallux present, thoughina 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 asa minute pimple-like elevation, 
with zo claw. In Phebetria there is a minute claw visible externally, 
whilst internally ¢wo 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 Diomedeinz has 
led to finding a similar one in some other birds usually considered to 
be three-toed, namely the Woodpeckers of the genera Picoides and 
Tiga. Inthesethe hallux consists ofits normal number of phalanges, of 
minute size, asisalso 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 may really exist in many birds commonly described as three- 
+ Bull. U.S. Nat. Mus. i. p. 22. 
2 Cf. Voyage of H MLS. ‘ Challenger:’ Report on the Anatomy of the Petrels, 
pp. 18, 14. 
