HYDEOCHELIDON LAEIFORMIS, BLACK TERN. 707 



extremity emarginate, slightly papillate; uiue-tenths long. Eima glottidis one-fourth 

 of an inch long ; sparsely jjapillate. 



The ahiuentary canal is exceedingly similar in all respects to that of Sterna. 

 CEsophagns, proven trienlus, and gigeriuin in a straight line, all of ordinarj' charaeters, 

 the former 3| to 4 inches long. Proventricnlar belt 0.3 to 0.4 wide, forming a complete 

 zone, as usual. Duodenal fold 1.40 long. Hepatic and cystic ducts short, opening 

 into intestine at the ordinary place. Lobes of liver of nearly equal size; their anterior 

 snrfiice convex, their posterior slightly concave; their apices divaricating, as usual, to 

 receive the heart between them, their inferior extremities in apposition. They are 

 connected by glandular substance. The chief fold after the duodenal is a short dis- 

 tance •ibove the cceca, and lies apposed to the posterior surface of the gizzard ; after 

 ■which the intestine proceeds in a slightly convoluted course to the cojca. These are 

 the shortest throughout the subfamily measuring hardly one-eighth of an inch in length. 

 Eectum moderately long (for this subfamily), measuriug six-tenths. Cloaca large and 

 globular; three-fourths long. Its posterior diviKi(m sn)all, but well marked. Orifices 

 of ureters and vasa deferentia in the usual place. The kidneys, as in Sterna, are 

 divided into five or six lobes by the segmentation of the middle portions. The whole 

 renal mass measures about an inch in length by six-tenths in breadth. The trachea 

 is about 2i- inches long, of the usual number of rings. It is flattened superiorly; 

 below it becomes perfectly cylindrical and narrower. The lower larynx is exceedingly 

 small, measuring only one-tenth of an inch across its widest part. Its sides are C(ra- 

 cave, its apices acute and projecting. Bronchial apertures extremely narrow, of an 

 oval, inclining to a crescentic, shape. The sterno-traclieales join the trachea only 

 one-fourth of an inch above the larynx. Bronchi of ordinary length, of about twenty- 

 two half rings. 



Syvomimy. — The first tenable binomial name of this species appears to be lariformu, 

 Linn., 1758, in adopting which I h<pe not to be acccused of arbitrary innovation. No 

 valid reason appears why Linnseus should not be adopted at this date, rather than at 

 1766, and in spite of custom to the contrary, this view is constantly gaining grouid. 

 I myself am entirely in favor of it. The changes it requires are not many, and they 

 are in some cases desirable ones, as, for instance, when we are furnished with Chalnra 

 pelagica (1758) instead of the unmeaning C. pelasgia of 1766 This bird is also the 

 S. fissipes, Linn. ; a name not commonly adopted until after Mr. Gray's rectificatien of 

 the synonymy, the term nigra (ex Briss.) having been generally employed. But iiiqra, 

 Linn., cleaily belong.s to Imieoptera, Meisuer. Other old names of this species are navia, 

 oliscura, and siiriiiamnisis, all based upon immature conditions of plumage. Latham 

 put naria down as S. Iiogsii var. B. Wilson renamed the species pliimhea, doubtless in 

 simple ignorance of the prior designations. 



I must continue to disagree with several ornithological friends, for whose opinions 

 I have great respect, in holding the American bird to be specifically identical. Never- 

 theless, in deference to their views, I have collated the synonj'm.V in two sets. 



In my review of the Sterninm, I state that " the birds of the two continents were first 

 formally separated by Bonaparte in his Comparative List of 18:i8." This is a slip of 

 the pen. Both' are there given as Hydrocheltdon vigrum ; he makes the distinction in 

 1856 (Tabl. Longip. C. E.), giving the American as Hgdrochelidoii surinamensis. 



Lieiitmaiit Warren's Expedition. — 9023, Loup Fork of the Platte. 

 Later Expeditions. — 54322, Wyoming. 



The Black Tern migrates both coastwise and over the water-conrses 

 of the interior. On the coast of North Carolina I saw none, in spring', 

 until the second week in May, when they became very abundant for a 

 few days and then disappeared on their way north. These spring birds 

 were always, so far as I ascertained, in full plumage. The Terns revisit 

 the same region very early, in advance of most of the migrants, in the 

 fore part of August, and proceed much more leisurely than in spring. 

 For about two mouths they were constantly to be seen hovering over 

 the marshes in airy troops, fluttering hither and thither like so many 

 Swallows or Night-ha^^■ks, busily foraging for iiiseuts. These fall 

 arrivals were chiefly young birds; and of the old ones, none were seen 

 still wearing the breeding dress, which, therefore, must be early laid 

 aside. These Terns, like the other smaller species, but just the reverse 

 of the large kinds, are perfectly familiar, or rather heedless, at all times. 

 In the spring, at their breeding resorts, they dash close down to an 

 intruder, repeating with angry vehemence their shrill crik, cn'k, crik ; 

 in the fall, when nearly silent, they are equally regardless of api>roaeh, 



