698 DR, r. CHALMERS MITCHELL ON THE 



Tarsal bridges. — The hypotarsus is complex in Balceniceps, 

 Scopus and Herons ; that is to say the proximal end of the shaft 

 is provided with two bony bridges through which the flexor 

 tendons pass ; in Storks these bridges are absent, and the tendons 

 lie in a gi-oove. 



Summary of Osteological Notes. 



Thei'e is a strong general resemblance between Balceniceps, on 

 the one hand, and S'cojms, Herons and Storks on the other. 

 Balceniceps stands alone in its general proportions, in the struc- 

 ture and relationship of the lacrymal, quadratojugal bar, atlas, 

 posterior lateral process of the sternum, and the humerus. 



Balce7iiceps and Scop>us agree, opposed to the others, in the 

 impervious nostrils, the union of the inner plates of the palatines, 

 jhe processes bounding the temporal cavity, the acrocoracoid 

 articulation of the clavicle, and the shortness of the tip of the 

 clavicle. 



Balceniceps, Scojms and Storks agree, opposed to the others, in 

 the basi-temporal plate, the complete interorbital septum, the 

 veiy small vomer, the shape of the posterior notch of the ster- 

 num, the absence of a spina interna, and of a median process 

 between the diverging arms of the furcula, and the presence of 

 a notch separating the posterior extremities of the ischium and 

 ilium, 



Balce,7iiceps and Storks agree, opj)osed to the others, in the 

 large procoracoid, and the smooth edge of the post-acetabular 

 ilium. Of the Storks, Tantalus shows the closest agreement with 

 Bakenicej^s in the occipital condyle, the paroccipital processes 

 and the basisphenoid. 



Balceniceps and Herons and Scopus agree, to the exclusion of 

 the others, in the proportions of the pelvis, and the complex 

 hypotarsus. 



I have been iinable to find any osteological points in which 

 Balcenicep>s agrees with Herons to the exclusion of the others. 



Systematic Position of Bal^i^.niceps. 



John Gould (22) named and diagnosed this bird in 1851. He 

 relied on external characters and compared it carefully with 

 Pelecanus, Grus, Arcleci and Cancroma. He came to the con- 

 clusion that it Avas the " Grallatorial type of the Pelecanida?." 

 He rejected alliance with Arclea and Gancroina apparently because 

 in the latter the nail of the central toe is pectinated, a character 

 which he thought to be wholly absent in Balceniceps. I have 

 shown (supra, p. 648) that much reliance cannot be placed on 

 this character. Undoubtedly there are many marked anatomical 

 characters common to Balceniceps and the Pelican. I may 

 mention the presence of a pyloric chamber of the stomach : 

 the division of the great pectoral muscle; the condition of the 



