SKELETON OE CETACEA. 



427 



a long and slender coracoid. In Euphysetes the triangle is more 

 equilateral, as it is in Ziphius and Hyperooclo7i. In DeljjhinidcB 

 the convex base of the scapula is usually the longest of the three 

 sides : the extension of the bone in the axis of the trunk is re- 

 markable in the Gangetic Dolphin 289 

 (^Platanista), in which the acromion 

 projects mid-way between the an- 

 terior basal angle and the glenoid 

 cavity. 



The humerus, figs. 159, 289, 53, 

 290, a, is remarkably short in pro- 

 portion to its thickness : the head 

 is large, hemispherical ; bent very 

 slightly out of the axis of the bone ; 

 with the outer or radial tuberosity 

 feebly marked in most, rather more 

 strongly in the Cachalots, and form- 

 ing a deltoid tuberosity: the shaft 

 becomes compressed and expanded 

 toward the distal end, which has 

 two ill-defined, flattened surfaces 

 for syndesmotic junction with the 

 radius and ulna. The latter, ib. 55, 

 usually sends backward an olecra- 

 non ; but this is not developed in 

 Platanista, where the ulna is broader 

 and longer than the radius : usually 

 the radius is the larger bone, as in 

 fig. 289, 54 : both bones are flat- 

 tened, shorter than the humerus in 

 Cachalots and Platanists, longer in 

 Whale-bone Whales, Bottle-nose 

 Whales {Ilyperoodon Ziphius), 

 Grampuses, Porpoises, Dolphins. 

 The contiguous epiphyses of the hu- 

 merus and antibrachials first unite 

 with their respective shafts : in an 

 old Cachalot and Delphinus Tursio,^ the radius and ulna are 

 anchylosed with the humerus, fig. 290, a. In a Southern Whale 

 the carpus, fig. 289, 56, consists of seven ossicles: the first on the 

 radial side answers to the scaphoid and trapezium : the second, 

 in D. Tiirsio, is wedged into a distal cleft between the radius and 

 ulna, and corresponds with the lunare in the Chelonian carpus and 



' xiAV , no. 2483. 



Bones of Pectoral fln : BaUcna australis. 



