REPORT ON THE ANATOMY OF THE PETRELS. 13 
The scutellation of the tarsi presents different characters in the Procellariide and 
Oceanitide respectively. In the former, in all the forms, the legs, which are often much 
compressed below the lower limit of feathering, are covered pretty uniformly by small 
scutellee of hexagonal shape (vide Pl. I. fig. 5,@). In the Oceanitide, on the other hand, 
though the back and more or less of the lateral aspects of the leg are so covered, the 
front of the leg is either, as in the genera Oceanites (Pl. I. fig. 1, a) and Fregetta 
(Pl. L. fig. 4, a), “ ocreate,” being covered for nearly all its length by a single long scute, 
or, as in Garrodia and Pelagodroma (figs. 2, a; 3, a), has a series of strong, well- 
marked, obliquely transverse scutelle, extending on to the external and internal faces 
of the leg for some distance. 
The hallux in the Tubinares is always extremely small, and in the genus Pelecanoides 
quite absent. When present it consists only of a single joint (wide wifra, p. 53, and 
Pl. VI. fig. 14), which, even when best developed, is very small and covered by a short, 
nearly straight, spur-like claw, which projects externally, some little way above the 
level of the other digits, and, being very small, may easily be passed over. In the 
Oceanitide this nail is extremely minute, considerably more so than in the Procellaride 
of similar size, but is always present’ and very straight and spur-like. In most of the 
Procellariidee it is larger and more curved : it is best developed proportionately, perhaps, 
in Pagodroma. 
In the Albatrosses the hind-toe is so minute that these birds are usually described as 
being three-toed, but this is not really quite cor- g P 
rect. In Phabetria the hallux externally only <q 0 
QR 
just appears, being represented merely by a 
slight pimple-like elevation, with a very minute 
claw. On dissecting away the skin, the pimple 
is seen to be connected with two minute bony I 
nodules, the basal one, which represents the 
metatarsal, more globular, the apical one more Fis. 2.—Rudimentary Hallux of the Albatrosses, of the 
natural size, except a. 
pointed and covered by the minute claw. 4, Predetria fuligi- EMipion ghalalin 
They are only connected by connective and nosa, showing the (represented in. sec- 
. > two ossicles, con- tion). 
fibrous tissue to the tarso-metatarsus,” and are nected together by 5, Diomedeu eculans, 
separated from each other by a considerable pate ce ss pointe Puen pe 
interspace, the whole having a total jextent of covered bya minute d. Thalassiarche cul- 
only 3 mm. (vide fig. 2, «). ER RE ae 
In Thalassiarche (culminata) and Diomedea (brachyura and exulans) this hallux is 
still more rudimentary, and there is not a trace of a nail outside. Still, on careful 
1 Mr. Dresser erroneously describes it as wanting in Oceanites (Birds of Europe, vol. viii. p. 503). 
2 The existence of the rudimentary hallux in Phebetria fuliginosa was first, I believe, pointed out by Dr. Kidder 
in his account of the birds of Kerguelen’s Land, Bull. U. S. Nat. Mus., vol. i. p. 22. 
