248 ANNALS NEW YORK ACADEMY OF SCIENCES 



been explained as a provision for enlarging the capacity of the mouth 

 (Kiikenthal) ; but their presence on the thorax can hardly be so ac- 

 counted for. Andrews has suggested that they may be a provision for 

 great expansion of the thorax, taken in connection with the fact that in 

 Balcenoptera the sternum is greatly reduced, is joined by only the first 

 pair of ribs and cos to-central articulations are present only from the 

 second to the fourth or fifth rib. Dr. J. Vaughan has suggested that 

 this extreme expansion of the thorax may be passive and would seem to 

 be called for if it can be assumed that the diaphragm relaxes during the 

 period of apnoea, when the animal is submerged. 



The heart was practically unrotated, its long axis nearly dorso-ventral 

 and not appreciably deviated to the left. Its chief internal peculiarity 

 was the form of the valve of the fossa ovalis, like a perforated thimble 

 attached all around to its base. There was, further, no Eustachian and 

 no Thebesian valve. These conditions have been previously described 

 by Knox and by Turner. 



The trachea was wide, short and covered as far as its bifurcation by a 

 thick walled muscular laryngeal sac. The structure of this is such as to 

 preclude the possibility of its acting as a reservoir. It may possibly 

 serve by its contraction to set up a current in the air within the capacious 

 bronchial tree, so aiding in the diffusion and utilization of the con- 

 tained air. 



The liver was massive and of simple contours; the stomach showed 

 four compartments ; the intestine had undergone rotation and an ascend- 

 ing colon, splenic flexure and descending colon — in a word, the left colic 

 loop of Bardeen was present and fixed ; the csecum was of moderate size, 

 bluntly rounded at the apex. The chief peculiarity of the situs viscerum 

 was the coUacation of almost all of the intestine together with liver, 

 spleen, pancreas and stomach in the preumbilical portion of the abdomen. 

 There was no foramen epiploicum, a condition recorded by Hunter of 

 certain whales. 



The genito-urinary tract resembles closely the description of Daudt 

 except that there is certainly no mesentery for the kidneys, nor was it 

 evident that there was any real asymmetry of the internal or the external 

 organs — the individual bein^ a female — other than could properly be 

 ascribed to the curvature of the foetus. 



The skull was remarkable for its rounded cranium, wide exposure of 

 the supra-occipital, enormous auditory bullas, straight axis and small 

 development of rostrum, orbital process and squamosal. 



There were thirteen pairs of ribs. The first rib was two headed on 



