COLYMBUS. 439 



Order PYGOPODES. 



For the characters of this order we cannot do better than quote the definitions given 

 in vol. xxvi. of the ' Catalogue of Birds ' : — 



" Skull holorhinal and schizognathous ; nares pervious ; vomer cleft posteriorly 

 for about J or ^ its length ; basipterygoid processes absent ; lachrymal not 

 extending dov^nwards to join the quadrato-jugal bar ; quadrate with an elongate 

 orbital process ; maxillo-palatine processes laminate, not rod-shaped ; dentary suture 

 of mandible more or less completely obliterated; angulare truncate posteriorly; 

 furculum without a facet for articulation with the acro-coracoid ; pre-ilia not rising up 

 to meet in the middle line above the fused neural spines of the synsacrum ; post-ilia 

 much longer than the pre-ilia and vertically compressed ; tibio-tarsus with the cnemial 

 crest produced upward far beyond the articular surface of the femur ; tarso-metatarsus 

 laterally compressed ; outer toe longest, Ehamphotheca simple. Nestling nidifugous." 



The Order contains two Families — the Divers and the Grebes. 



Fam. COLYMBID^. 



The Divers have the hallux on a level with the fore toes, the latter being united by 

 a web ; the tail is composed of eighteen or twenty short stiff feathers {cf. Grant, 

 Cat. Birds Brit. Mus. xxvi. p. 485). The family consists of a single genus, Colymbus. 



COLYMBUS. 



Colymbus, Linn. Syst. Nat. i. p. 220 (1766); Grant, Cat. Birds Brit. Mus. xxvi. p. 486 (1898). 



American ornithologists employ the name Urinator of Cuvier for Colymbus of 

 Linnaeus, 1766, holding that, in the 1758 edition, Linnaeus used Urinator for the 

 Grebes. We prefer, however, to adhere to the Stricklandian Code and to recognize 

 the genera of the 1766 edition. 



Five species of Colymbus are known, all of them breeding far north in both 

 hemispheres, and migrating southward in winter. 



1. Colymbus glacialis. 



Le Grand Plongeon, Brisson, Orn. vi. p. 105, t. 10. fig. 1 \ 



Colymbus glacialis, Linn. Syst. Nat. i. p. 221 ' ; Grant, Cat. Birds Brit. Mus. xxvi. p. 495 \ 

 Urinator immer (Briinn.), Baird, Brewer, & Ridgway, Water-Birds N. Amer. ii. p. 446 *. 

 Urinator imber (Gunn.), A. 0. U. Cieck-l. N. Amer. Birds, p. 75=; 2ud ed. p. 3'; Herrera, 

 La Nat. (2) i. pp. 188 ', 330 «. 



Ptil.Mem. Supra nigricans, plamis grisescenti-schistaceo late marginatis, pileo et coUo postioo concoloribis 

 niTicantibus, nitore viridi inconspicuo, dorso postico et uropygio brunnescentioribus ; corpore toro 



