NO. 1322. A NEW PROCELSTERNA— FISHER. 561 



breast and on throat, which parts are grayish. Sides of head and 

 neck darker than adult. Black portion of orbital ring much wider 

 and more conspicuous than white. White area over orbital ring as 

 in adult. Malar stripe white. Measurements in millimeters: Wing, 

 157; tail, 80; culmen, 17; tarsus, 23. 



Nestling. — Recently hatched (male) cotype, No. 18865-1, U.S.N.M. 

 Completely covered with soft down. Pure white Ijelow. Crown 

 white, sides and back of neck very pale buff}^ Ends of wings white; 

 inner portion of alar, and the humeral and spinal tracts brownish gray 

 (down white at tips and brownish gray below). Feet greenish gray, 

 bill black. 



Egg. — Bluntly ovate and broadly elliptical ovate (two specimens). 

 Ground color dull creamy white; in one specimen not thickly marked 

 with roundish rod-shaped, Y-shaped, U-shaped and irregular small 

 spots of clay. Color, light sepia, and wood brown, shell marks show- 

 ing various shades of bluish gray. In this specimen the spots are 

 rather evenly distributed over the whole &^g. The other specimen 

 has more numerous smaller and more regular spots about the size of 

 dust shot, which are scattered over the whole Qgg,, but are thicker at 

 the blunt end. The gray spots are larger and more numerous than the 

 brown ones. The two specimens measure 36.5 by 26 and 39 by 27 

 millimeters. 



In some respects the present form is intermediate between Procel- 

 8terna cerulea (Bennett) and P. cinerea (Gould). This is true of the 

 size, in a general way, and also of the color of the under parts. The 

 under parts of cerulea are fully as dark as the back, which (in an old 

 skin collected by T. R. Peale, Dog Island, Low Archipelago) is more 

 ashy than that of saxatiUs. Procelsterna saxatilis shows its closer 

 relationship with cinerea in the light lower parts and light gray 

 wedges on the four outer primaries. As mentioned above, however, 

 it is smaller than cinerea., with conspicuously shorter wing, and 

 shorter and slenderer bill. The under wing-coverts are pearl gray 

 instead of white, and the breast, sides, and lower tail-coverts are 

 decidedly gra}^, whereas in cinerea' the lower parts are almost white 

 and entirely so on the belly and lower tail-coverts. The general tone 

 of the plumage of cinerea is ashy, but in mxatills it is bluish. 



We tir«t saw this handsome tern off the French Frigate Shoals, 

 between Necker and Laysan. Here it undoubtedly nests on a precipi- 

 tous rock, which rises 125 feet above the sea. It was at this locality 

 that Henry Palmer, Rothschild's collector, mentioned seeing a little 

 gray tern," which he was unable to secure. He probabl}^ meant the 

 present species. 



We found Procelsterna saxatilis very soon after we landed on 



"Avifauna of Laysan, etc. By Walter Kothschild (Henry Palmer's Diary, Pt. 1, 

 pp. IX and XII) . 



