440 CETACEA. 



(Esophagus. — This is 1 foot in length, and 3-75 inches in breadth at the base 

 of the epiglottis; 6 inches behind this, it contracts to 2-50 inches, dilating again at 

 the orifice of the stomach to 3 inches. It is capable of great distension. The 

 muscles consist of two layers. Posteriorly, the first or external layer passes from 

 within outwards, the fibres in the middle being longitudinal, or nearly so ; the lateral 

 fibres are oblique, winding roimd the side of the tube to the ventral aspect, and are 

 so crowded together at the side, that they produce the appearance as if this portion of 

 the tube were provided with a special muscle. They terminate in a longitudmal line 

 corresponding to the side of the trachea. Some of the external oblique fibres give 

 off long loops which run across the oesophageal wall, in some cases at right angles. 

 The second or internal layer on the posterior aspect is transverse, and appears to be 

 continuous at the lower end of the oesophagus, with the obliquely transverse thin 

 layers of the interval between the tracheal margins. 



Microscopic structure. — The mucous membrane of the oesophagus near its lower 

 end is of considerable thickness, and the papillse are long and filiform ; the epithelial 

 cells being large and polygonal. I have not been able to detect any glands besides 

 the ordinary mucous glands, which are most numerous near the anterior end of the 

 tube. 



Belations of stomach in the adult. — The left division of the stomach is almost 

 wholly hidden by the liver, and lies slightly posterior to the right sac. When in- 

 flated, it is placed rather obliquely across the abdomiaal cavity in an antero-posterior 

 dhection, with its apex directed downwards to the right side, many inches anterior 

 to its oesophageal orifice, which latter is slightly dorsally placed to the opening 

 between the two stomachs. The right division lies obliquely across the abdomen 

 hidden by the liver, excej)t along its lower margin, which describes a curve of nearly 

 half a circle. It rests on the left half of the first sac, and its apex is directed down- 

 wards to the right side, tending backwards and shghtly upwards and then backwards, 

 downwards and outwards to the left, to its junction with the third cavity. Tlris 

 latter lies behind, and is nearly covered by it. The oesophageal orifice is opposite the 

 sixth rib, 7 inches from its distal extremity, and its apex is opposite and distant 2 inches 

 from the distal end of the eighth rib. With the specimen placed on its back, this 

 section of the stomach (second cavity) reaches the sternal attachment of the second 

 rib, and, when fully inflated, it rises from 2 '50 to 3 inches above the level of the 

 oesophageal orifice. The tlmd sac Ues posterior to the second, and passes to the left 

 nearly as far as the mesial line, where it is continuous with the duodenum which 

 runs downwards and shghtly to the left on a line with the lower margin of the mass 

 of the stomach and posterior to the intestines. 



Relations of stomach in the foetus. — The mass of the stomach lies to the left 

 of the mesial line of the body, and the second or right cavity hides the left, which 

 lies behind it. The apex of the fu'st cavity is directed backwards, so that the sac is 

 almost transverse to the longitudinal axis of the abdomen. The second sac occupies 

 the greater part of the left half of the abdominal cavity, but extends slightly to the 

 right of it. Its apex is bent upon itself, passing backwards and downwards to the 



