716 EHYNCHOPS NIGRA, BLACK SKIMMER. 



obsolete toward the joint, and have exceedingly oblique margins. Laterally and pos- 

 teriorly there are jylates, small, regular, smooth, of a polyhedral (mostly hexagonal) 

 Bha)ie, larg'est and flattest on the sides of the tarsus, smaller and more roughened 

 behind and on the joint. The toes superiorly are defended, as is the tarsus, by scutella, 

 the webs by small reticulated plates ; on the inferior surfaces of both the "plates are 

 nearly obsolete. The middle and outer toes are of much the same length, the inner 

 much shorter, the tip of its claw reaching the base of the middle claw. The hallux is 

 of moderate length for this family ; its claw short, stout, blunt, little curved. The 

 anterior claws are all long, slender, depressed, moderately arched, rather acute, the 

 inner edges of all dilated, that of the middle one most so. The iuterdigital memhraues 

 are of the ordinary widtla and amount of emargination. The feet in life are carmiue- 

 red, in the dried state dull yellowish, with a tinge of pink. 



The wings are excessively long and powerful. The primaries are broad, their 

 rhachides stroug, outer five or six of a somewhat falcate shape, narrowing rather sud- 

 denly when near the tip to their only moderately acute and rather rounded apices. 

 The secondaries are short, broad to their very tii)s, which are rounded, with a very 

 slight amount of excision of the extremities of their outer webs. The superior surface 

 of the Aviugs is glossy black, like the back; their inferior aspect, except a narrow line 

 along their metacarpal edge, white; this color deepening toward the ends of the pri- 

 maries, first into grayish, and then into blackish. The first six primaries are concolor, 

 black, pure and deep on their outer web, lighter and of a brownish tinge on their 

 inner; their rhachides black. The inner four primaries are brown ; their inner webs, 

 and the tips of both webs, white. The secondaries are white, with a space of dark 

 brown occupying nearly the whole of their outer and a small part of their inner 

 webs. The amount of brown is least on the outer ones ; increases on each feather suc- 

 cessively, till the last four secondaries and the tertials are brownish-black, except a 

 narrow apical margin. 



The tail is of moderate length, being contained rather less than three times in the 

 wing. It is moderately emargiuate. The feathers are rather narrow, the central pair 

 rounded at their tips, the lateral ones converging to a very obtuse point. The upper 

 t^iil-coverts are short, being scarcely half the length of the tail ; the inferior ones, how- 

 ever, reach within a short distance of the tips of the central rectrices. The tail and 

 its under coverts are white, the inner webs of all the rectrices more or less obscured 

 with dark brown, deepest on the central pair. The superior coverts are black like the 

 back, except the outer row on each side, which are white. 



Crown of the head, its sides just below the eyes, the back of the neck, and whole 

 upper parts, pure glossy black. The forehead, cheeks, sides of the head below the 

 eye, sides of the neck, and whole under parts, pure white ; tinged in life, during the 

 nuptial season, with rosy. 



Dimensions. — Length (of males), 20; extent of wings, 49; wing from flexure, 16 to 

 16.50: from apex of longest secondary to tip of first primary, 6; tail, 5.50 to 6; depth 

 of fork, 1 to 1.25 ; upper mandible along culmeu, 3 ; along gape, 4 ; height opposite 

 middle of nostrils, 0.60; width at same j)lace, 0.45; length of nasal fossa, 0.75; of 

 nostrils, 0.40 ; under mandible along gonys, 3.75 ; along fused tomia, 3.60 ; along gape, 

 4.50; from feathers on its side to tip, 4.10 ; its depth at deepest part, just anterior to 

 beginning of symphysis, 0.60 ; deptli .T.t; tip, about 0.25 ; length of longest oblique 

 stria, about 0.40 ; tibite bare, 1.10; tarsus, 1.45; middle toe and claw, 1.30; outer toe 

 and claw, 1.20 ; inner toe and claw, 0.95 ; hallux and claw, 0.35. 



The preceding descriijtion was taken from a large and very perfect specimen obtained 

 in Florida. The dimensions are perhaps somewhat greater than the average of exam- 

 ples, but not more so than is frequently found to be the case. Individuals vary 

 greatly in size, many apparently equally adult examples being much smaller than the 

 one whose dimensions I have just given. I believe that Audubon is quite correct iu 

 saying that the females are smaller than the males. They will not average probably 

 more than 16 or 17 inches in length, by about 42 in extent of wings, as he has said. 

 I have also found the bills to be much thinner, lightei", and weaker. In colors the 

 sexes hardly differ notably. 



Yonng-of-ihe-year. — Bill smaller than in the adult, thinner, weaker, its ridges less 

 sharply defined, and the two mandibles of less xinequal length. General proportions 

 less than in adult. Bill brownish-black for three-fourths of its length, fading into dull 

 born-color just at its tip, lightening into more or less intense flesh color, or light red- 

 dish, toward the base. The strite on the sides of the lower maudible are as numerous as, 

 but much less distinct than, in the adult. Tail shorter and less deeply emargiuate. 

 Legs and feet dull light reddish. Entire upi)er parts a rather light grayish-brown, 

 deepest on the wing-coverts and tertials ; each feather with a tolerably broad margin 

 and tip of white, broadest and most conspicuous on the wing-coverts and tertials. 

 Forehead, sides of the head below the eyes, the neck ail round, the edge of the fore- 

 arm, inferior surfaces of the wings, and whole under parts, white. Primaries almost 

 exactly as in the adults, except that the innermost have more white, and there is a 



