164 PROCEEDINGS OF THE ACADEMY OP 



Pachypiila cccrulea, Illiger, Prod. 1811, p. 275. Steph. Shaw's Gen. Zool. 1825, 



xiii. p. 252. 

 Procellaria similis, " Forster's Drawings, No. 86." Forster, Descr. Anim. ed. 



Licht. 1844, p. 59. 

 Procellaria Forateri, Smith, 111. S. Afric. Birds, pi. 54. But not of Latham, 



which is Prion vittalus. 



Ualilat. Antarctic Ocean. Australia. 



Color. There is a short and not very conspicuous infra-ocular white line, 

 and a superciliary streak of the same color; but not, however, running far 

 down on the auriculars behind the eye. Above the bird is of a clear cinere- 

 ous or grayish blue ; extendirg as delicate clouding around the sides of the 

 breast ; and deepening on the head, most of the wing-coverts, the outer edgc3 

 and tips of the four outer primaries, into brownish ash. It is chiefly the lesser 

 wing coverts that are thus darkened; most of the greater ones being nearly as 

 clear as the back. The secondaries and tertials are clear cinereous, edged 

 and tipped with white; their inner webs being almost wholly of this color. 

 The iuner vanes of all the primaries, but particularly of the first four, are 

 almost wholly pearly white except at their tips. The upper tail coverts ere 

 concolor with the back. The exterior pair of rectrices are white, with dark 

 brown shafts; the next two are colored like the back; the rest similar ex- 

 cept that a fuscous hue deadens the cinereous towards the end of the feathers, 

 and their tips are squarely, trenchantly, and purely white ; each for an in- 

 creasing dit-tance from without inwards. Forehead, cheeks, lower auricular.- 1 , 

 under surface of wings and whole under parts of the body pure white. 



Younger birds may be known by a less decidedly cinereous or bluish gray 

 tinge of the upper parts ; which tend more or less strongly towards brownish. 

 The forehead is not pure white but mixed with about an equal amount of 

 brownish ash. I have never seen specimens entirely fuscous or brownish 

 ci'<ereous below; but think it probable that such a state of plumage charac- 

 terizes very young birds. 



JJimrnsions. Chord of culmen 1*12 ; height of bill at base -45 ; width slightly 

 less. Tarsus 1-25; middle toe and claw 1-60; outer do. 1-50; inner do. 1 37. 

 Tail 350; wing 8 to 9. 



There is no other known Fetrel with a square tail, conspicuously tipped 

 with white. This peculiarity is mentioned in the various descriptions of the 

 authors cited above in the list of synonyma, so that there is no difficulty in 

 identifying their names. The similis of Forster* is said to have " rectrices 12 

 omnes apice can dido-fa sciatae " which positively determines the species, al- 

 though that author is in error in saying that it has the bill " non pectina- 

 tum." 



PSEUDOPRION Cones. 



Chs Lateral lamellae of upper mandible normally developed, their surfaces 

 vertical. Lateral outline of bill straight. Dorsal outline concave to the 

 unguis. Unguis comparatively large, its chord forming more than a third of 

 tbe total length of the culmen. Commissural edge of upper mandible not dila- 

 ted. Inferior mandibular lami straight, divaricating at an acute angle; the 

 lateral sulcus apparent. Nj groove for reception of fringe from upper mandi- 

 ble, which is either quite obsolete or imperfectly developed towards the end of 

 the bill. InterramrJ space narrow, triangular, well feathered. Extension of 

 feathers on side of lower mandible not further than those on culmen. Tail 

 moderately graduated. 



Type. Prion lurtur Gould. 



la amplification of the differences between the so-called Prion Banksii, tur- 



* Concerning which Prof. Liechtenstein says very erroneously, "Species obscura, ulteriori ex- 

 aniinj relinquenda. A Pr. vittata {Pachyptila) uou esse divers-im nisi eetats suspicor." 



[May, 



