212 PROCEEDINGS OF THE ACADEMY OF 



u'Echm,ophoTUs, Podiceps, Sylbeocyclus ; possibly one or two others, but most of 

 tbe genera invented or used by Kaup, Bonaparte, and others, are untenable, 

 representing only specific characters. Sylbeocyclus (type S. minor) is the con- 

 necting linlv between the two subfamilies. 



Families and subfamilies o/LONGIPENNES. 



There are but two families of macropterous swimmers, that moreover shade 

 into each other so insensibly and completely that the condition of the nostrils 

 is sometimes almost the only character. Thus Thalassoica glacialoides is a pure 

 gull, even to colors, with tubular nostrils. In fact, I know of no positive un- 

 qualified character but this that will reach through the whole of the two 

 families as a distinguishing mark. Still there are others of greater or less 

 significance. Both the families are clearly difl'erentiated into several sub- 

 families, which are much easier to define. 



Fam. Procellariid^. — Nostrils tubular, lateral or superior, united or sepa- 

 rate. Bill variable in shape, always hooked; its corneous envelope (always?) 

 iu several pieces ; rarely laminate. Wings long and pointed (one exc.) Tail 

 variable in shape; usually small, never very long, of 12 — 16 (rarely 10??) 

 rectrices, of which the central are never suddenly long-exserted. Feet pal- 

 mate ; hallux present, minute, functionless, or absent. Tarsal envelope 

 sometimes continuous (a unique feature among swimmers I). Truly pelagic 

 birds, independent of land. Al trices. 



Three strongly marked subfamilies, thus: 



Subfam, DiomedeiiiK. — Nostrils lateral, disjoined, horizontal. Feet tridac- 

 tyle. Wings extreme, in length of humerus and ulna, and with highest num- 

 ber of remiges (fifty) known among birds, but only ten primaries, as usual. 

 Genera : Diomectea, Phcebelria, founded on sulcation of mandible and shape of 

 tail. 



The albatrosses, in size, contour, and length of wing, repeat the Pelecanidse 

 in their own family; in length of wing they are only otherwise approached by 

 another Steganopod family, — Tachypelidce. But still a constricted group, with 

 no aberrant forms. 



Subfam. Procellariince. — Nostrils superior, horizontal, united in one double- 

 barrelled tube. Too various in other respects to be concisel}' characterized. 

 Still, the central or typical aspect of the family ; throwing out feelers in 

 several directions. 



One group comprises the smallest species, T^ith pointed wings, elastic flexi- 

 ble primaries, rather long tail, variable in shape; the most slender and long- 

 est legs of the family. These birds are pelagic Cypselidx ! Genera: Oceano- 

 droma, Cymochorea ( = Thalassidroma Bp. nee. Vig.), Ilalocyptena (cauda 

 cuneata), Procellaria (ex hinn. = Thalassidroma Vig. auctt.), Oceaniles (i)odo- 

 theca continua), Fregetta, Pelayodroma. 



Another comprises heavier Ijirds, of medium size, with long hooked bills, 

 long, strong, pointed wings, and short rounded (rarely pointed) tail. It seems 

 to occupy the very centre of the family. But it has a strong pygopodous 

 feature in the tibial apophysis of at least some of its members, thus pointing 

 to the Loons and Grebes. These are "Shearwater" Petrels. Genera: Maja- 

 queus, P'riofinus (= Adamastor Bp.), approaching Fulmar Petrels, and Piiffinus 

 (including Nectris), from which Thiellus only differs iu a longer, more pointed 

 tail. 



A third group consists of the gull-like Petrels, called " Fulmars." Tliese 

 are among the largest of the family ; stout, thick-set ; tail of 14 — 16 rectrices, 

 well-formed ; wings moderate, tor this family ; bill stout, moderately hooked. 

 A group scarcely worth retaining as distinct from the last, for of its three 

 genera, Fulmarus and Thalitssoica are almost side by side with Priofinus ; and 

 the other, Ossifraga, with Majaqueus. Ossifraga points to the albatrosses, Tha- 

 lassoica to the gulls ; the last hardly differs from Fulmarus. 



[Dec. 



