aRT. 13 ANATOMY OF CHINESE FINLESS POEPOISE HOWELL, 15 



buttons. The last vertebra to have a minute neural canal is the six- 

 teenth in two instances, seventeenth in another, and eighteenth in a 

 fourth. The last vertebra to bear a spine is the sixteenth save in 

 49544, in which there may be said to be a small spine present on the 

 seventeenth. The first vertebra to have a small foramen upon the 

 dorso-lateral aspect of either side of the centrum is the seventh in 

 four cases and the eighth in two. The more cranial of the chevron 

 bones are large and well developed, but without my personally hav- 

 ■ ing cleaned the skeletons it is imposible to state their exact number 

 with any confidence. 



THORAX 



Ribs. — As already stated, there are 12 pairs of thoracic ribs in five 

 of the animals studied, 13 in one and 14 in another. The first seven 

 have both capitular and tubercular attachment, the former being 

 upon the centrum of the vertebra next craniad to the tubercular 

 articulation. This is so in all cases save in one of Allen's specimens 

 in which there were but six ribs in this class. The remaining ribs 

 are attached only to the transverse processes or diapophyses. The 

 first rib is much the stoutest and the others are inclined to become 

 more slender in caudal sequence. The parts of the ribs usually 

 designated as costal cartilages in most mammals are completely calci- 

 fied. The first pair of these is especially robust and is attached to the 

 sternum in peculiar fashion. In the only individual in which the 

 majority of these sternal ribs are still connected with the sternum 

 there are four pairs directly attached, and a fifth pair indirectly to 

 the extreme caudal portion by cartilage. This seems also to be the 

 case in two of the other specimens before me, while in the remaining 

 three there are probably but three pairs with direct attachment and 

 a fourth with a cartilagenous union; but the ribs are now 

 disarticulated. 



SternuTn. — The sternal complex consists of a single bone, 

 representing the fusion of an unknown number of component parts. 

 It is shorter and more specialized than in the great majority of 

 cetaceans and there is much variation in its shape, just as illustrated 

 by Allen in the case of his specimens. The measurements of those 

 before me, given in the same sequence as in Table 1, are 95 by 75 

 mm., 72 by 79, 99 by 82, 81 by 78, 65 by 56, and 89 by 83 mm. In 

 each case the first figure given represents sagittal length, and the 

 second, transverse breadth; so it is seen that the sternum may oc- 

 casionally be broader than long. In two of the present specimens 

 there are sternal fenestrations (caused by lack of ossification be- 

 tween centers) similar to those illustrated by Allen in his Plate 3. 

 The latter also shows the manner of articulation of the first sternal 

 rib, craniad with the cranial process and caudad with the lateral 



