216 PROCEEDINGS OF THE ACADEMY OF 



Fam. Tachypetid^. — Bill rather long, stout, strongly hooked, its covering 

 not continuous. Nostrils very small. Gular sac highly developed.* Wings 

 and tail excessively long and strong; the latter deeply forked, r2-feathered. 

 Legs extraordinarily! short, well forward, but scarcely used. Tarsi plumose : 

 middle claw pectinated. Unsurpassed flyers: scarcely swimmers ; not divers. 

 Taken from Petrels. Technically one subfamily. Genus : Tachj/petes. 



The tarsal ptilosis, and pectination of the middle claw, are unique in the 

 subclass ; the webs are more deeply incised than usual. In wings, tail and 

 bill these birds are modified Petrels. 



^ Fam. Phaethontid/e. — Bill medium, stout, straight, sub-serrate, paragna- 

 thous, its covering continuous. Nostrils small, but pervious. Gular sac smallest 

 in the order ; wholly feathered. Wings long and pointed. Tail moderate, 

 but with long-exserted, filamentous median rectrices ; 16-feathered. Feet 

 well forward, short and stout; horizontal position of body necessitated. Ex- 

 cellent flyers ; good swimmers ; not divers. Taken from Terns. Technically 

 one subfarailj'. Genus : Phoelhon. 



The gular sac is scarcely more than rudimentary, and it is fully feathered ; 

 the nostrils are comparatively well developed. The bill is almost exactly 

 that of a Tern. The filamentous tail feathers are rarely found outside 

 Sternince. The general resemblance to a Tern, in physical characters, as well 

 as mode of life, is too obvious to require further comment. 



So we see that each main group of water birds has been laid under contri- 

 bution to form this scattering polymorphic family, a comprehensive mask for 

 the rest. 



Family and suhfaviilies of LAMELLIROSTRES. 



A completely circumscribed group, of onl}' one family, Anatithe, whose 

 characters are those of its order. The only break in the family is at the point 

 of departure from JVatatores to Grallatores, where the way is opened for the 

 passage from Anatidx by Fha-nicopterzia. There are six subfamilies, just as 

 there are six families of the preceding order. These are mainly distinguished 

 by the varying combination of characters common to several ; but some intro- 

 duce peculiar features. Of t'ae latter, Mergmia are the furthest removed, perhaps, 

 from all the rest. They have consequently been considered by some as a 

 separate family. But a merganser is scarcely or not more different from a 

 duck than a swan is. Regard for equivalency of groups therefore requires it 

 to be placed as a subfamily of Analidie. 



Fam. ANATIDJil (chars, as above). 



Subfam. Ci/ffninx. — Neck of extreme length for this family. Rill stout, high, 

 and compressed at base, wide and depressed at tip, longer than head, sides 

 ])arallel. Nail narrow. Lamelhe of upper mandible vertical, in one row. Soft 

 skin of bill reaching towards, or to, eyes. J Wings ample : the inner remiges 

 highly developed. Tail short, rounded, indefinite!}' many {20-l-)-feaihered. 

 Tarsus short, reticulate. Feet large ; webs always full. Hallux small, 

 elevated, with a small lobe. Trachea convolute, entering sternum (always?). 

 Sexes similar. Species of largest size in the family, proverbially elegant 

 swimmers, strong flyers, poor walkers; do not dive. Genera: Cyt/nus, Olor, 

 Coscoroba, Chenopsis. 



Subfam. Anserincn. — Neck lengthened; shorter than in the foregoing, longer 



* The Frigate-birds have more of a pouch than they are usually given credit for. Mr. 

 Oassiri's figure, in Oillis' U. S. Naval .\stroa. Exp., is not exaggerated. 



t The abbreviation of the tarsus in this case probably represents the extreme of tliis 

 feature in tlie class Avts. 



J The genus (Jhoristnpus, Eyton, apparently Anserine rather than Cygnine, is said to pos- 

 sess this character ("rostrum longum acuminatum (^era ad oculos tenJente." — Eytou, 

 Mon. Anat.) If so, the character is not unexceptionable. 



[Deo. 



