HYDROCHELfDON LARIFORMIS, BLACK TERN. 707 



extremity emarginate, slightly papillate ; uine-tentlis long. Rima glottiilis oue-fourth 

 of an inch long ; sparsely papillate. 



The alimentary canal is exceedingly similar in all rfespects to that of Sterna. 

 ffisopbagus, proventricnlna, and gigerinm in a straight line, all of ordinary characters, 

 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 

 surface 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 above the cceca, and lies apposed to the posterior surface of the gizzard ; after 

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

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

 Rectum moderately long (for this subfamily), measuring six-tenths. Cloaca large and 

 globular ; three-fourths long. Its posterior division small, but well mariicd. Oritices 

 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 tbe middle portions. The whole 

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

 is abojit 2^ 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 con- 

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

 oval, inclining to a cresceutic, shape. The sterno-tracheales join the trachea only 

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

 two half rings. 



Sijuoiiywy. — The first tenable binomial name of this species appears to be lariformis, 

 Linn., 1758, in adopting which 1 hope not to be acccuse<l of arbitrary innovation. No 

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

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

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

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

 pelagica (175H) instead of the unmeaning C. pcJasfjla of 1766 Tbis bird is also the 

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

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

 Linn., clearly belongs to hitcojjtera, Meisner. Other old names of this species are iioria, 

 obncura, and .sttrinamensis, all based upon innnature conditions of i)luniage. Latbaiu 

 put tiaria down as <S'. hoi/ftii var. B. Wilson renamed the species pUtmbea, doubtless in 

 simple ignorance of the prior designations. 



I must continue to disagree with several ornithological friends, for whose oj)inions 

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

 theless, in deference to their views, I have collated the synonymy in two sets. 



In my review of the Stcruhia; I state that " the birds of the two continents were first 

 formally separated by Bonaparte in bis Comparative List of 1S38." Tbis is a slip of 

 the ])en. Both are there given as HijdrocheUdon viyriitn ; he makes the distinction in 

 18r)6 (Tabl. Lougip. C. R.), giving the American as IlydrochcUduii nurinamcimis. 



Lieutenant Warren''s Expedition. — 1)023, Loup Fork of the Platte. 

 Later Expeditions. — .")4322, Wyoming. 



The Black Tern migrates both coastwise and over the water-cour.ses 

 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 lor a 

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

 Avere always, so iar as I ascertained, in lull plumage. The Terns revisit 

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

 fore i)art of August, and jwoceed much more leisurely than in springy. 

 For about two months tlu'y were constantly to be seen hovering' over 

 the marshes in airy troops, tluttering- hither and thither like .so many 

 Swallows or Niglit-hawUs, busily foraging" for inse(;ts. These fall 

 arrivals were chiell.v young- birds; aud of the old oues, m)iu' wore seen 

 still wciiring- the brt-ediug- dress, which, therefore, must be early laid 

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

 of the large kinds, are itei-feetly familiar, or rather heetlless, at all tiuu's. 

 In the spring', at their Ineediug resorts, they dash elose down to an 

 intruder, repeating with angry vehemence their shrill rrik, cril:., vril: ; 

 iu the fall, when nearly silent, they are e<]ually regardless of ai)i>roach, 



