82 PROCEEDINGS OF THE ACADEMY OP 



more concerning the validity, and in that event, regarding the generic rela- 

 tions, of this supposed specie3. 



?? 8. On the same page where fasciolata is described, Dr. Tschudi goes on 

 to speak of a Petrel of which he saw several examples some degrees further 

 south, but of which he was unable to procure specimens. The mantle was 

 dark gray, the head blackish, the neck somewhat darker ; the feet and bill 

 black, the wing feathers blackish, the abdomen grayish white. In size it 

 hardly equalled pelagica. " Ich wage daher nicht mit Bestimmtheit zu ent- 

 echeiden, ob diese Vogel zu einer Species gehoren, noch dem von mir 

 beobachteten einen Namen zu gaben." A few pages further on (p. 190), the 

 supposed species is named Thai, dubia. As from the circumstances of obser- 

 vation there is extreme liability to error, and, at all events, great uncer- 

 tainty, Thai, dubia had better quietly await more reliable data before claim- 

 ing recognition. 



The remaining species constitute the second group of Procellariea;, separ- 

 able from the preceding group by exceedingly trenchant characters. In 

 the first place, the species all stand, high : the lengthened tarsi much exceed 

 in dimensions the long toes, while at the same time the tibiae are greatly 

 elongated, and bare of feathers for the greater part of their extent. The 

 claws are very different from those of the first section, being broader than 

 high, depressed, not compressed, and always more or less rounded and 

 obtuse. The tail varies, being either rounded, square or forked ; but when 

 the latter, it is never so deeply forked as in oceanodroma, etc., of the first group. 

 The wings are very long, much surpassing the tail. 



Three distinct genera constitute this section. 



g VI. OCEANITES, Keys, et Bias. 



This is the genus of which our common " Wilson's Petrel" is the type, 

 first named Oceanites by Keyserling and Blasius Wirlbelth. Europ. ii., 1364, p. 

 238. It is in many respects the most distinct and remarkable genus of the 

 Procellariea;, being widely diverse in all its characters from all others. It 

 may be well here to define its limits with precision. 



Oceanites, Keys, et Bl. (Type Proc pelagica, Wils. nee Linn.) The bill is 

 short, weak, compressed, its sides a little concave, its tip attenuated, the 

 convexity of the culmen along the unguis comparatively little ; it is less than 

 half as long as the head, about half as long as the middle toe without the 

 claw, about two-fifths the tarsus. The nasal tubes, instead of rising obliquely 

 upwards and forwards, as in the genera of the first section, have their dorsal 

 outline perfectly straight and horizontal. The wings are exceedingly long 

 and acute, and the proportions of the primaries different from that which 

 obtains in any genus hitherto considered ; the second primary very much 

 the longest; the first fully equal to the third ; the fourth very greatly shorter 

 than the first. The tail is of moderate length and nearly square, being 

 neither much forked nor much rounded, large and full, the feathers broad 

 to their very tips. The legs are the most peculiar. The elongated tibiae are 

 bare for an inch or more. The very long tarsi present the remarkable feature 

 of having their anterior and lateral aspects covered with one smooth unbroken 

 podotheca or " boot," resulting from the fusion together of the ordinary plates 

 and scutellae. Posteriorly the plates remain pretty distinct. The toes, 

 though very long, are, without the claws, only two-thirds the tarsus. The 

 hallux is so extremely minute as to be discernible only on close inspection, 

 when it is apparent as an exceedingly short, acute claw. The anterior claws 

 are flattened and broad, and scarcely at all curved. The species of the genus 

 are among the larger in size, with much the colors of Procellaria proper. 



Of the genus as thus constituted, the following species are known to me: 



1. Oceanites oceanica, (Kuhl). 



Procellaria pelagica, Wils. Am. Orn., 1808, vi. p. 90, pi. Ix. Procellaria 



[March, 



