OSTEOLOGY OF SCOPUS UMBRETTA AND BALyENICEPS REX. 411 



a single median channel, with its sides equally conspicuous, the 

 whole not extending any great distance down the shaft. This 

 is likewise the case in Scopus, but the bottom of the channel is 

 thrice slightly guttered for the accommodation of tendons. In 

 Ardea, as has been shown on a previous page, this process 

 is entirely different. Distally, the tarsometatarsus of Scopus is 

 distinctly ciconine, in that the lateral trochlea are produced 

 further backwards and the middle one further downwards than 

 they are in Ardea. The proportions of the 2^odal digits and 

 their characters are more inclined Stork-wards, than they hint 

 anything to us of a pronounced Heron-type. 



In the skeleton of Scopus now at hand the humerus has a 

 length of 91 cms., the ulna of 11 cms., and the carpo-metacarpus 

 of 47 cms. ; in the hinder extremity, the femur measures 4-9 cms. 

 in length, the tibio-tarsus 11*2 cms., and the tarso-metatarsus 

 7*4 cms. 



Turning to the skeletons of some of the near allies of Scopus 

 among the Ardeidm, Parker has said "the genus Cancroma, 

 might be placed subgenerically to Balceniceps; yet although 

 the former has the most outspread bill, it is less aberrant 

 from the true Herons than the latter. Indeed the Balceniceps 

 seems, as it were, to have borrowed characters from the 

 Umbre {Scopus) — a bird not so nearly related to the Herons as 

 itself — and also from the Ibises on one hand, and from the 



macrodactylous Eails on the other." "The skull of 



Cancroma would have been a perplexing study without the 

 rest of its skeleton, which is remarkably normal, being that of 

 a true Heron shortened in joint and limb.^ Now add to 

 that shortening of the joints and members of a truly Ardeine 

 skeleton which we see in Cancroma the necessary robust, and 

 we have the osseous structure of Balceniceps at once." 



" The only real difference between the vertebrae of Cancroma 

 and those of Ardea is the comparative shortness of those of the 

 former; the vertebrae of Balceniceps are simply those of a 

 gigantic Boat-bill." 



" The sternal apparatus of Baloiniceps is the most extra- 



^ I have carefully examined the entire skeleton of Cancroma zeladoni (No. 

 18,385 of the U.S. Nat. Mus. Coll.), and can fully endorse this opinion of 

 Professor Parker's. — R. W. S. 



