ALBINO— ALLANTOIS 



distinguishable by its yellow or light-coloured legs, while the other, 

 the D. hrachyura of Temminck, its young being the D. nigripes of 

 Audubon, has those limbs dark or black. Both of them seem to 

 occur in summer in Bering Sea, Avhile they occasionally appear 

 along the shores of China and California ; but nothing can yet be said 

 as to their precise range. It remains to mention the smaller species 

 of the genus, one of which, D. cauta, described by Gould, is not 

 much infei'ior in size to the preceding, and omng to its wary 

 disposition, indicated by the trivial name it bears, is extremely rare 

 in collections. These are all known to seafaring men as Molly- 

 y[/ mauks — a corruption of Mallemuck — and chiefly frequent the 

 Southern Ocean, as does also the Sooty Albatros, which, from its 

 wedge-shaped tail, has been placed in a genus of its own, and passes 

 as Phcebetria fuUginosa. 



ALBINO (coll. n. albinism). A case of Heterochrosis, pro- 

 duced by the partial or total absence of the normally-present black 

 pigment in the feathers and other parts. In complete albinos the 

 pupil and iris are red, owing to the blood-vessels shining through 

 these otherwise strongly pigmented parts. A lesion of the pulp of 

 a growing feather not unfrequently prevents the deposition of pig- 

 ment therein, but the pulp recovers as a rule after one or more 

 moults (see Colour). 



ALECTOEIDES, an Order proposed by Temminck in 1820 c/. 

 {Man. d'Oni. ed. 2, i. p. xcv.) to contain the genera Fsophia (Trump- /j/^ J 

 eter), Dkholophus (Seriema), Glareola (Pratincole), Palamedea, and '^ ^^-^'f^ 

 Chauna (Screainier). Sundevall subsequently (A". VeL Acad. Hand- (^/Ja^^i/i 

 lingar, 1836, p. 120) substituted Otis (Bustard) for Glareola, but // 

 wholly dropped the group in his Tentamen (1872-73) wherein these 

 forms are differently disposed. The Order has, however, been ad- 

 mitted by several other systematists, and among them by Mr. Sclater, 

 Avho, in 1880, made it include six Families (see Introduction). 







ALECTOEOMOEPH^, according to Prof. Huxley's arrange- 

 ment {Proc. Zool. Soc. 1867, i^p. 456, 459), the fifth group of 

 SCHIZOGNATH^, corresponding practically with the Gallin.-e of 

 Linnaeus ; and, omitting the genera Opisthocomus (Hoactzin) and 

 Menura (Lyrp>bird), with the section Gallinacei of Illiger's Easores. 



' ALK, the old and apparently the more correct form of Auk. 



ALLANTOIS (from dAAas, a sausage). A sack-like structure, 

 which during the very early development, of the embryo grows out 

 / from the posterior gut into the body cavity, and extends rapidly all 

 round the embryo in the space enclosed by the false amnion, forming 

 then with the latter a highly vascular inner lining of the eggshell. 

 This bag receives urine, and takes on respiratory functions in 

 embryonic Birds and Eeptiles. Towards the end of incubation the 



