120 BIRDS OF THE COMMANDER ISLANDS. 



ajffinis are marked as females ; it may be, therefore, that all the specimeus of 

 the former are males, and the latter all females. A glauee at Dr. Fiusch's^ 

 table of measurements (Verb. Zool.-Bot. Ges. Wien, 1879, p. 208) shows 

 that there is not so very great difference between the sexes, although the 

 average of his five males is larger than that of my tliree specimens. 

 While it thus remains to be seen whether L. schistisagus really is larger 

 than L. affinis there is one character to be derived from the measure- 

 ment which at once separates the two, viz, the shortness of the middle 

 toe of the latter as compared with the tarsus. In L. schistisagus tarsus and 

 middle toe, with claw, are practically of equal length (average differ, 

 ence, 1.5°""; maximum, 3""°), while in L. apnis the former is much longer 

 than the latter (average, 12"'" = ^ inch; maximum, 14"""; minimum, 

 Qmiu^ That this difference is not accidental and due to the scantiness 

 of the material is clear from the fact that we find the same proportion 

 in the seven specimens measured by Finsch, and in a specimen meas- 

 ured by Meves.* In the five males as given by Finsch the average dif- 

 ference is 14'^^ ; maximum, 17""™; minimum, 12™°^. It is possible that 

 Finsch's measurements do not include the claw; but, on the other hand, 

 I am not certain whether he measures the tarsus in front or from the 

 side, and in the latter case his measurements would agree very nearly 

 with mine. Even granting that the length of the tarsus as given by 

 him is that of its greatest dimension, and adding the length by which 

 the claw extends beyond the toe, the average difference between toe 

 with claw and tarsus would not fall much short of lO™'", while L. schis- 

 tisagus, in having the tarsus and middle toe of equal length, agrees with 

 L. argentatus and L. cachinnans. 



There is a decided difference in the color of the soft parts of the two 

 species. As will be seen from my notes (Oru. Fxpl. Kamtsch, pp. 6S, C9) 

 in L. schistisagus the eyelids are " reddish violet gray," the angle ot 

 mouth pale yellow, and the feet flesh color of a rather deep reddish hue. 

 All observers of L. affinis agree that its eyelids are orange-red and the 

 feet yellow. Mr. Seebohm (Ibis, 1876, p. 452) says: "Like both these 

 species [L. cachinnans and L. fuscus] it has yellow legs, and the circle 

 round the eye is brilliant vermilion, or the color of a Seville orange. 

 * * * In winter, no doubt, the legs lose their yellow color and become 

 grayish white, but the orange-red eyelid is retained." In the Ibis for 

 1879, p. 162, the same author speaks of it as ''this yellow-legged Her- 

 ring-gull." Meves (Oefv. Sv. Yet. Akad. Handl., 1871, p. 786) describes 

 the bird shot by him as having " the feet of a beautiful lemon-yellow 

 color, as in Lams fuscus,''' and " the angle of mouth and eyelids orange- 

 red." Dr. Finsch (op. cit., p. 269) states that his No. 513 had the " eyelids 

 vermilion, legs dirty ocher-yellow;" in Xo. 510 the eyelids were minium 

 red, and the legs orange ocher-yellow. The colors of the soft parts, con- 

 sequently, differ iu the two species even more than those of L. argentatus 



* Cf. also Saunders's remark, P. Z. S., 1878, p. 172, to the effect that the foot of L. 

 affinis as compared with the tarsus is smaller than that of either L. argentatus, L. 

 cachinnans, or L. occklentalia. 



