NATURAL SCIENCES OF PHILADELPHIA. <3 



arrangement and nomenclature. A comparison of the respective mono- 

 graphs on this subject, by the two distinguished authors just mentioned, 

 affords a striking illustration of the widely diverse results which may be 

 arrived at on any investigation, when two co-workers entertain radically 

 opposite views concerning generic or specific relations. The endeavor to 

 harmonize such conflicting opinions is a matter of no little difficulty ; but 

 as the truth probably lies somewhere between the two, it is perhaps worth 

 while to make the attempt. With every facility in the way of books and 

 specimens which the Philadelphia Academy and the Smithsonian Institution 

 afford, I may perhaps have been so fortunate as to have fixed the quite 

 numerous species with some degree of precision, and to have settled some 

 points of synonymy. Concerning the genera adopted, each one must judge 

 of their agreement with nature, or the reverse, according to his own opinion 

 upon the question of what constitutes a generic group. 



The family Procellaridse is naturally divisible into three subfamilies : the 

 Diomedeinse, the Procellarina^, and the Halodrominse. These are readily 

 eharacterizable, aside from any consideration of other features, by the posi- 

 tion and shape of the nasal tubes. In the Diornedeina? these tubes are 

 entirely disconnected, and placed one on each side of the bill. In the Pro- 

 cellarinse they are united, situated at the base of the culmen, and open more 

 or less horizontally forwards. In the Halodrominas their position is as in 

 the Procellarina?, but their apertures are directed vertically upwards. 



The subfamily Procellarinae is composed of several grpups, or assemblages 

 of genera and species, which constitute the "sections" of Prince Bonaparte's 

 arrangements. These divisions are the Fulmarese, the Daptionea?, the Prio- 

 neae, the Puffinea?, and the Procellarieae. The genera composing each of 

 these are more intimately allied to each other than they are to the genera of 

 any other section : and we have consequently an exceedingly convenient and 

 perhaps not unnatural means of dividing the very- extensive subfamily into 

 readily characterizable lesser groups. That section which forms the subject 

 of the present article the Procellariea; is the largest and at the same time 

 the most marked of these groups. It may readily be distinguished from the 

 other groups by the following peculiarities : 



Section PHOCELLAR1EJE. 



The species are all uniformly of small size, there being found in this 

 section the very smallest of natatores, and none of the species exceeding 

 eight or nine inches in total length. In form, most of the genera are delicate 

 and graceful, none being as robust as is usual in most of the genera of other 

 sections. The colors of the group vary exceedingly. A large proportion of 

 the species are fuliginous black, varied more or less with white; but in some 

 genera there is seen some variety in the pattern of coloration. Bright 

 colors, however, are never found. The bill is of moderate or very small 

 size, always shorter than the head or tarsus, rather wide at the base, its sides 

 rapidly converging towards an attenuated compressed decurved tip. The 

 nafal tubes are long, elevated, and conspicuous ; subcylindrical in shape, 

 inclined forwards and somewhat obliquely upwards ; the septum between the 

 narcs thin, delicate, and quite perpendicular; the nasal aperture circular; 

 the tubes in length always at least nearly half as long as the culmen. The 

 wings are long; the first primary, contrary to the general rule in this family, 

 always shorter than the second, sometimes only as long as the fourth. The 

 second primary is always longest, the third intermediate between the fourth 

 aud second. The primaries are acutely pointed, a little falcate, and strong, 

 though very flexible and elastic. The tail is very long, but is exceedingly 

 variable in shape, being even, forked, emarginate, rounded, or cuneate. The 

 legs are ; !y slender, delicate, compressed usually, much elongated. 



1864.] 



