10'4 MB. W. H. FLOWER ON THE OSTEOLOGY OF 



tions of such attachments, though it is possible that the cartilaginous hinder margin 

 may have been connected with another pair. 



In Platanisfa, according to Eschricht, four pairs of ribs are attached directly by their 

 cartilages to the sternum, and the form of this bone has nothing in common with that 

 of Inia. The manubrium is flat and triangular, very broad in front, with a straight 

 anterior edge, and without either of the processes so promment in Inia. This is 

 succeeded by a distinct body, ossified from two lateral centres, and a xiphoid process 

 wholly cartilaginous in the young specimen described. Many of the true Dolphins have 

 two conspicuous pairs of processes on the manubrium sterni, evidently for the attach- 

 ment of muscles— one projecting forwards and outwards, in front of and within the sur- 

 face for the attachment of the first pair of sternal ribs, the other rising fi-om the lateral 

 border between the surfaces for the articulation of the first and second sternal ribs, and 

 directed somewhat backwards. These are especially developed in Monodon. It is to 

 these that the processes of the sternum of Inia appear to correspond, though much 

 modified in direction. The sternum of Phoccena entirely wants these processes; 

 otherwise it presents some resemblance to that of Inia in its breadth, flatness, and in 

 consisting of a single piece. 



The pectoral limbs of Inia are described by d'Orbigny as "larges, longues, et 

 obtuses ;" and the present skeleton fully corroborates this account. 



The scapula (Plate XXV. fig. 3) does not present that -singularly aberrant character 

 which is one of the most peculiar features of the skeleton of Platanista, but conforms 

 more to the ordinary type of the Dolphin-family. Its superior costa is long, and with 

 a tolerably regular arch ; the anterior and posterior costse (of which the former is 

 slightly the longer) are much hollowed out, so that the lower half of the bone is 

 narrower from side to side than in most Dolphins. Both the acromion process and 

 coracoid are very long, flat, and expanding and truncated at their extremities. The 

 glenoid fossa is large. 



The principal dimensions are : — 



/( 



Extreme height, fi'om glenoid fossa to middle of superior 



costa 37 



Extreme breadth 4-8 



Breadth of body at root of acromion process 1 "2 



Length of acromion 1 '7 



Length of coracoid process I'S 



Length of glenoid fossa 1 '2 



Breadth of glenoid fossa U"9 



Tlie humerus is unusually long in proportion to the other segments of the limb, and 

 very simple in its character. The tuberosity is very small ; but it is probably not com- 

 pletely ossified. The neck is but shghtly marked. The distal end of the bone is 



