S( III 1/1'K, SKI WHALE. 445 



tions of peritoneum. Thus there is left for the closely packed coils of the small intestine an 

 oblong space extending from the diaphragm, rostrad and on the left, to the median surface 

 of the right kidney, caudad and ventrad. The loop of the duodenum is anchored to the pos- 

 terior parietes as is also the arch of the colon which loses its mesentery above the level of the 

 transverse portion of the duodenum. 



The postumbilical division of the abdomen is very narrow. It is contracted at its com- 

 mencement by the projecting kidneys and, ventrally, by the large mass of the urachus and 

 hypogastric arteries. Into the pyramidal interval between these project a few coils of the 

 sn:all intestine. Caudad of the kidneys the broad ligament divides the space into a dorsal 

 compartment containing the colon and a ventral one containing the bladder. The ventral 

 compartment is limited caudad by the reflection of the peritoneum from the neck of the bladder 

 to the uterus. The dorsal compartment is prolonged as a narrow recess between the rectum 

 and vagina, and eventually is brought to an end close to the perineum. 



(Esophagus. The intra-abdominal segment of the oesophagus has a very considerable 

 length, measuring from the diaphragm to its cardiac orifice 10 mm. It descends with a slight 

 sinistral inclination on the dorsal aspect of the first gastric compartment, in reference to which 

 it is placed also somewhat to the right, as Jungklaus 1 has pointed out. On the left it is defined 

 by a shallow furrow, while to the right and ventrally it is separated from the stomach by a deep 

 incisure, which in the natural condition of the parts is filled with rather firm connective tissue. 

 Caudad its relief gradually merges in that of the first compartment. The conformation of the 

 cardiac orifice corresponds with the external character of this junction. Above and on the 

 right it is marked by an arched ridge, which diminishes to the left, while below, its dorsal wall 

 is continued into that of the stomach without demarcation. The lumen is marked by low 

 longitudinal ridges; immediately below the diaphragm it is open, having a transverse diameter 

 of 2 mm., but distad as it becomes applied to the stomach, its walls are in contact. The walls 

 here are about 1 mm. in thickness and the tube as a whole is slightly flattened dorso- vent rally. 



Stomach. Four compartments are present exclusive of the duodenal ampulla, which is 

 clearly marked off from the stomach by a sulcus ectally and by the flaring funnel of the pylorus 

 within. This enumeration agrees with that of Pilliet and Boulart, 2 and with the more recent 

 results of Jungklaus, who to a careful resume of the literature has added his own observations, 

 based so far as Balcenoptera is concerned, upon three foetuses of B. musculus, the youngest 

 measuring 63 cm. While conforming in the main to Jungklaus' description, this foetus shows 

 marked differences in the conformation of the third compartment. The minor peculiarities in 

 the shape and proportions of the other divisions are probably referable to the smaller size, 

 possibly also to the species of this foetus. The whole organ is admirably preserved. 



The first compartment is too little expanded to deserve Hunter's appellation of egg-shaped. 

 It is widest at its middle, thence diminishing towards both extremities. The fundus is bluntly 

 rounded, almost truncated in external view. Here both muscularis and mucosa are thickest; 

 then become thinner towards the apex of the stomach, which does not correspond accurately 

 with the junction of the first and second compartments, but is formed by the second alone as 

 in older fretuses (Jungklaus). The long axis is directed caudad, to the left and somewhat dorsad, 

 so that the fundus rests against the arch of the colon, and the right margin forms almost a right 



_ _ _ 5 



1 Jungklaus. F. Der Magen der Cetaceen. Jena. Zeitsch. f. Naturwiss., Bd. 32, 1898, p. 1. 



- Pilliet ct Houlsirt. I/estonmr des Cetaces. Jour, de 1'Anat. et de la Physiol., An. XXXI, 1895. 



