NATURAL SCIENCES OF PHILADELPHIA. 137 



even invading the throat. In immature individuals, also, the lateral inferior 

 caudal tectrices may be more extensively hued with plumbeous black. They 

 are never, however, so much darkened as is usual in obscurus or opisthomelas. 



This species may be always recognized among its congeners by the follow- 

 ing combination of characters: its peculiar dimensions (see above), joiued 

 to the very dark upper parts, this color descending far on the sides of the 

 head and breast, leaving a conspicuously white under eyelid ; the almost en- 

 tirely white under tail coverts and the comparative shortness and character- 

 istic degree of roundness of the tail. 



This is so very distinct, and at the same time so well known a species, that 

 it hardly requires comparison with any other. The features in which the P. 

 yelcuanus differs from it will be pointed out under the head of the latter. 



Puffinus Yelcuaxus, Bp. ex Acerb. 



Procellaria yelkouan,* Acerbi, " Bibliot. Ital., 1827, cxl., Agost. p. 294;" 

 et "Bull, des Sciences Nat., 1829, xvi. p. 463. Schlegel, Monog. Proc. 

 Mus. Pays-Bas, 1863, p. 29. Puffinus yelkouan, Bonaparte, Comptes 

 Rend. Tab. Longip. , Id. Consp. Av. ii. 1856, p. 205. 



Habitat. More eastern portions of the Mediterranean Sea ; especially in the 

 Black Sea, and in the vicinity of the Bosphorus. 



With this species, admitted by the majority of modern authors, I am ac- 

 quainted only through descriptions. This is specially to be regretted, since 

 authors are at variance regarding its characters and affinities, and are not even 

 entirely agreed upon its specific validity. Bonaparte considers it to be the 

 representative of obscurus in the Black Sea and vicinity, and says that it is 

 smaller than that species (being only 10 inches in length) and has a slenderer 

 bill. Dr. Schlegel, on the contrary, considers it as most intimately allied to 

 anglorum, which it replaces in that locality. As far as I can jud<2e from a 

 careful study of published descriptions, I entirely agree with Dr. Schlegel in 

 opinion. On comparing it with anglorum, Dr. Schlegel has found it to differ 

 as follows : In the greater elongation of the point of the wing ; in the color of 

 the upper parts being lighter and rather tending to grey than black, as is 

 also the color of the dark feathers of the crissum ; and in the uniform deep 

 gray of the lateral under tail coverts, these latter being, in anglorum, blaek 

 on their outer, and white on their inner webs. 



The following detailed measurements are given by the same author, taken 

 from, individuals coming from the Bosphorus, near Constantinople. They are 

 to be compared with those of anglorum, already given on a previous page. 

 Wing (from the carpus), 8-33 to 8-66 inches and hundredths. Tail, 2-40 to 

 2-60. Bill along culmen, 1-20 to 1-50 ; height, -28 to -33 ; width, -40. Nasal 

 tubes, 16 to -20. Tarsus, 1 66 to 1-80 ; middle toe, 1-58. 



Puffinus obscurus, Vieill. ex Ginel. 



Procellaria obscura, Ginel., Syst. Nat., i. pars ii. 1788, p. 559. Lath., 

 Ind. Ornith., ii. 1790, p. 828, et auct. antiq. Vieillot, Nouv. Diet. H. 

 N. 1817, xxv. p. 423. Puffinus obscurus, Bonap., Synop., 1828, p. 371. 

 Vieillot, Gal. Ois., 1834, ii. p 230 , pi. 292. Audub., Bds. Amer., 

 1844, vii. p. 216, pi. 458. et al, auct. recent. Nectris obscura, Kuhl, 

 Beitriige Zool., 1820, p. 147, pi. xi. fig. 11. Cymotomus obscurus, Mac- 

 gillivray, Man. Orn., 1844, ii. p. 13. " Puffinus I'kerminieri, Lesson," 

 fide Bp. Puffinus floriolanus, Musau Beroliensis," fide Bp. 

 Habitat. The warmer portions of the Atlantic Ocean, especially the Gulf of 

 Mexico, and the coasts of the Southern United States ; abundant in the Ba- 

 hamas and Bermudas. Wanders as far north as New Jersey, and is accident- 

 ally found in Europe. Apparently replaced in the corresponding latitudes of 

 the Pacific Ocean by my Puffinus opisthomelas. 

 For so long known a species, the present has remarkably few synonyms, 



* I find this barbarous name Tariously spelled yelkouan, yelkuan, yelkoan, etc. 1 li..vt seea 

 fit to modify it insomuch that it may present somewhat of a classical aspect. 



1864.] ' 



