684 STERNA HIRUNDO, COMMON TERN. 



is flattened and suboval; its distal extremity a little elongated, so as to give it some- 

 ■svliat of a cordiform contour. It is evidently not very powerful, its muscles being 

 hardly a tenth of an inch thick. The tendinous portion of its parietes is of small ex- 

 tent. Its cuticular lining is dense and firm, and thrown up into somewhat irregular 

 but chiefly longitudin.al folds. Corresponding elevations and depressions are found on 

 the inner surface of the proper parietes of the organ. There are no pyloric valves, but 

 only corrugations of the cuticular lining at this orifice. 



The intestinal canal is very short, measuring only between twelve and thirteen 

 inches between the pylorus and anus. The duodenal fold is about one and a half 

 inches in length. The pancreas stretches the whole length of the concavity between 

 the two folds, and appears as if double, there being an elongated, narrow, flattened 

 mass of the glandular substance on each side of the fold. After fornung this fokl the 

 intestines become convoluted and coiled upon each otiier to within three or four inches 

 of the cceca. There another regular loop or fold of the intestine occurs, nearly as 

 large and perfect as the duodenal one itself, against which it is opposed for nearly its 

 whole extent, and connected by reflections of the mesentery. 



There are two cceca coli, situate about one and a half inches from the anus. They 

 differ greatly from those of Lestriditicc and Larincv, in their extreme brevity. They 

 measure only about two-tenths of an inch in total length, and are so closely applied 

 and bound down to the colon that they might readily be overlooked. 



The " large " intestine is exceedingly short, straight, and scarcely, if at all, larger 

 than the small intestine. It preserves a pretty uniform width to near the anus, where 

 it suddenly expands into a capacious globular cloaca. The cloaca is coujpletely 

 divided into two parts — a larger anterior and internal portion, and a smaller posterior 

 and external. The latter is a slight pouch, or cul-de-sac, partially separated from the 

 former by a projecting transverse reduplication of the liniug membrane. Just above 

 the edge of this fold, at the extremity of the inner compartment of the cloaca, there is 

 on each side of the median line a small oval depression, surrounded by a corrugated, 

 sphincter-like elevation of mucous membrane, in which the efferent ducts of the 

 urinary and seminal organs terminate. 



The kidneys are quite jjeculiar in shape. The entire renal mass is nearly as long as 

 broad, and in shape almost perfectly rectangular. The upper lobes have but a slight 

 convexity of contour, and are but little larger than the lower. Each kidney is divided 

 into from four to six irregularly rectangular or polyhedral masses. Tbese lobes are 

 more or less completely separated from each other, but are closely coaptated, the sides 

 and angles of each mass being adapted to those of the masses which lie about it. 

 The ureters, formed by the union of the efiVrent ducts from each one of these masses, 

 run along nearly x^arallel to each other on each side of the median line of the spine, at 

 a little distance from it, converging somewhat toward their termination to open in the 

 cloaca, as already described. 



The testes lie immediately superimposed uj)on the superior lobes of the kidneys. 

 Their size varies greatly with age and season. The vas deferens runs backward iu 

 close relation to the ureters, to terminate in the above-mentioned depressions on each 

 side of the cloaca. 



The other organs of this species do not diff'er sufficiently from those of Larus to re- 

 quire special mention. 



Bihliofiraphy. — This is one of the "antique" species, though its synonyms are com- 

 paratively few. A chief point that arises is, whether tlie name '' hirinido " belongs here 

 or to the Arctic Tern {mai-rura, Naum,). The name has been with much reason re- 

 feri'ed to the latter, where it probably belongs; but it scarcely seems necessary to 

 make the change in this instance. The earlier diagnoses may apply to either, and, in 

 fact, probably included both, for it will be remembered that the two were not gen- 

 erally distinguished until about 1820. Linnaeus' hirundo may as well be kept for this 

 species, with which it is commonly associated in ornithological record. Hirundo of 

 Briinnich, Faber, and Fabricius, is a|)parently macrura; hirutido of Richardson is fors- 

 teri. Brisson called the bird Sterna major, a name of course to be disregarded in binom- 

 inal nomenclature. Eyton has it S. viarina, after a pre-Linnieau writer. " Wilsoni, 

 Bp.," and '■^ fluviatiUs, Naum.," are the two most fiinily-established syuouyms; but the 

 latter only arose upon reference of hirundo, Linn., to macriira, while, as I have shown, 

 the former has no basis at all. 



It is somewhat siiigjular tbat the "North American range of so common 

 and well known a species as this shonld not be better made out than it 

 is. A similar uncertainty respecting at least its winter range seems to 

 prevail in the matter of its European distribution. In this country it is 

 attributed to Brazil by Pelzeln, but this is the sole extralimital record 

 I have found, except Dr. Bryant's Bahaman quotation. Messrs. Sclater 

 and Salvin do not give it among Neotroi)ical LarUkc. The truth prob- 

 ably is, that it does not proceed beyond the United States, as a rule at 



