540 PROCEEDINGS OP THE ACADEMY OF 



white front, etc. At first sight it was referred to T.re(/ius,h\it on closer exami- 

 nation several important discrepancies were observed. The bill, though jugt 

 about as long as in rcr/ius, was very decidedly smaller, weaker, with the angle 

 at symphysis less developed ; it was of a clear straw-yellow, and in size and 

 shape about intermediate between regius and elegans. The lateral tail feathers 

 appear broader and rounded at their lip, instead of tapering and attenuated. 

 An important difference is seen in the feet, the middle toe and claw being de- 

 cidedly longer than the tarsus, instead of equal to it. Mr. Sclater did not label 

 this bird, and I am equally uncertain what name to apply. It seems to be not 

 at all improbable that it may be the S. cayana^ of Latham, and, if so, would 

 substantiate Gambel's position, for it is certainly not the bird he named regia. 



Thalasseus elegaxs Gamb. 



Sterna elegans, Gambel, Pr. A. N. S. Ph. iv. 1848, 129. Lawrence, Gen. Rep. 



Birds, 1858, 860. Atlas, pi. xciv. 

 Thalasseus elegans, Gambel, J. A. N. S. Ph. 2d ser. i. 1849, 228. 



DiAG. — Th. Thalassco regio similis; sed multo minor, rostro graciliore, digito 

 medio cam ungue tarso breviore ; corpore subtus rosaceo-albo. 



Habitat. — Coast of California. 



The most striking morphological character of this species, as compared with 

 its nearest ally, T. regia, is the comparative length of the tarsus and toes. In 

 regia the middle toe is, with the claw, just as long as the tarsus ; while the 

 same parts in elegans are very considerably shorter. 



This beautiful species has been so accurately described by its discoverer, and 

 its affinities so correctly indicated, that any further remarks upon these points 

 would be de trop. It is as yet almost unknown in cabinets. A very fine speci- 

 men, in winter plumage, has been deposited in the Smithsonian by J. Hepburn, 

 Esq., and is the original of the plate abore cited. It agrees minutely with 

 Gambel's description. 



TUALASSEUS ACUFLAVIDUS (Cabot). 



Sterna Boysii, Nuttall, Man. Orn. ii. 1834, 21G. Sed non Lath., ITSO. 



Sterna can'iaca, Audubon, Orn. Biog. iii. 1835, 531. Id. B. A. vii. 1844, 87. 



Sed non Gmel., 1788. 

 Sterna acuflavida, Cabot, Proc. Bost. Soc. N. H., 1837, ii. 257. Lawr. Gen. P>,ep. 



1858, 860. 

 Thalasseus acuflavidus, ? 



DiAG. — T. Thalasseo cantiaco statura, forma, colorib usque omnino similis ; sed 

 margine alba pogonii interni remigis primce angustlore, nee in apicem pennas 

 porrecta. 



Habitat. — Atlantic Coast of North America, ranging into the Antilles in winter. 



The young of the year is considerably smaller than the adult (wing h inch 

 shorter) as is usual in this subfamily. The bill is shorter and weaker, and is 

 without any very distinct definition of angles and ridges. It is brownish black, 

 the extreme point only 3'ellowish. The crown, front and nape are brownish 

 black, variegated with white, the white touches very small on the front. The 

 uppei" parts are as in the adults ; but everywhere marked with irregularly-shaped, 

 but well-defined spots and transverse bars of decided brownish black. There is 

 no well formed occipital crest, until after the first moult. The primaries are like 

 those of the adults. The tail, however, is very different. The feathers for 

 three-fourths their length are of the color of the back; this color gradually 

 deepens, until towards the tips it becomes brownish black, — each feather having 

 a terminal irregular edge left whitish. The tail, in shape, is simply deeply 

 emarginate, the outer feathers being but slightly longer than the second. 



In winter the yellow tip of the bill of the adults decreases in extent and in- 

 tensity of color ; the front is white, either pure or speckled with black ; the 

 crown variegated with black and white; but the long occipital crest, which does 



[Dec. 



