36 



Suborder VI. STEGANOPODES. 



Dcsraoguathous birds in which the angle of the mandible is 

 truncated and the hind limbs are always very short — most so in the 

 Frcijatklai, — the four digits being connected together by a web. 

 The skull is without supraorbital grooves on the frontals for glands. 



The tarso-metatarsus and tibio-tarsus are short and stout ; the 

 former is compressed from front to back iuferiorly, and has a distinct 

 depression on the proximal portion of the anterior surface ; its distal 

 trochleas descend nearly to the same level, the second one being often 

 longer than the fourth (the reverse of the arrangement found in the 

 Auseres). The phalangeals are nearly always very long and slender. 

 The distal extremity of the tibio-tarsus is not deflected markedly 

 towards the inner side, and the oblique extensor bridge is devoid of 

 a tubercle ; the cnemial crest is slight. 



The femur is short and stout, with a shallow anterior trochlear 

 groove, generally a slight popliteal depressiou, and a pit on the 

 posterior aspect externally to the cctocondyle (fig. 8). 



The coracoid is relatively long, constricted at the middle, and 

 much expanded distally ; the shaft is more or less curved anteriorly ; 

 and there is almost invariably a facet on the anterior aspect of the 

 proximal extremity for the articulation of the furcula ; the sternal 

 articular surface is short, with a well-marked inner ledge, and never 

 occupies the whole width of the bone ; the subclavicular process is 

 small, and has no perforation at its base. The V-shaped furcula is 

 united to the sternum either by suture or anchylosis ; its much dilated 

 superior extremities do not reach the sternum, and they usually 

 carry facets corresponding with those on the coracoids. 



The relative length of the wing and the proportions of the com- 

 ponent bones vary greatly. The humerus has the proximal extre- 

 mity but little enlarged, with a well-marked but narrow subtrochan- 

 teric fossa, the head only slightly more prominent than the tro- 

 chanter, and bounded interiorly by a distinct groove for the humcro- 

 coracoidal ligament, the deito-pectoral crest slightly develojjed, no 

 ectepicoudylar process, and a more or less elongated surface for the 

 brachialis anticus. 



The skull has a transverse hinge-joint between the frontals and 

 the rostrum. 



