144 ODOXTORNITHES. 



Measurements of Scapula. (Apatomis celer, No. 1734.) 



Left. Right. 



Length of scapula, -- 52.5 mm 



Greatest diameter, across humeral articulation, 5. l mm 



Least diameter, through humeral articulation, 2. 



Length of acromial process, from base, 3.5 



Diameter of shaft, above humeral articulation, 3. 3. 



The Coracoid. (Plate XXIII and XXIX.) 



In the genus Ichthyomis,. the coracoid is a strong bone, much widened 

 at the proximal end, where it articulates with the sternum in an elongated 

 groove on each side. These grooves, and consequently the coracoids in 

 their natural position, cross the median line in front in such a manner 

 that the right coracoid is external to, or in front of, the left, as in the 

 herons and their allies, and in some other birds. The proximal end is 

 much expanded, as in Colymbus, but the bone is less robust than in that 

 genus. The external part of the expanded portion is thin, and is short in 

 the line of the axis of the bone. The inner angle of the expansion is 

 produced and acute, as in Ardea. 



The shaft of the coracoid is flattened, nearly or quite as far as the 

 articular surface for the humerus. This surface is nearly flat, suboval, and 

 somewhat less than twice as long as broad. The articular surface for the 

 scapula is a nearly hemispherical pit, or cup, in diameter about equal to 

 the transverse diameter of the humeral articulation. It is placed just 

 within the lower end of that articulation, instead of almost wholly below it, 

 as in Apatomis. 



Just beneath the articular face for the scapula, is a foramen, per- 

 forating the base of a strong sub-scapular process, which is crushed and 

 broken away from most of the specimens preserved. This process is 

 triangular in shape (Plate XXIX, fig. 16), and much like that seen in 

 Ardea Jierodias, Linn. Below and beyond the articular faces, the 

 coracoid is flattened vertically, and, at the end, it is expanded ; but, as in 

 Ardea, it presents no facet for articulation with the clavicle, which is 

 unknown in Ichthyomis. The shaft of the bone is hollow, with thin walls. 



