560 DE. J. MURIE ON THE ANATOMY OF THE SEA-LION. 



The thick, well-developed muscular coat of the oesophagus of Otaria afforded me 

 ample opportunity of testing whether its composition was similar or otherwise to what 

 Dr. Rutherford ' has described in the gullet of the Sheep, Ox, and Dog. According to 

 him, layers of fibres cross obliquely like the letter X, but are not continuous spiral fibres 

 from pharynx to stomach — rather decussating in evenly distributed bundles or loops, 

 which form short parallelograms crossing three times. Thus, while strength and 

 rapidity of transmission in either direction is gained, the tube retains a more or less 

 uniform thickness of wall. I find, therefore, after tracing the fibres with great 

 caution, in the hardened and distended gullet of this Seal, that they perfectly corre- 

 spond with the structural conditions extant in the Ruminants and Carnivore examined 

 by him. Indeed it becomes evident, on consideration, that the diverse direction and 

 interdigitating of the fleshy fibres of the three massive constrictors of the pharynx are, 

 with some modification, modelled after the same fashion. Those fibres at the opposite 

 extremity of the tube, near the cardiac orifice, are thicker than at the middle of the 

 gullet, and they pass on to the stomach, tending to form the so-called constrictor or 

 oblique bands of the cardiac end of the stomach. The deep layer of fibres has the 

 greater obliquity of the two. 



Cuvier's 2 and Meckel's 3 observations (unnoticed by Rutherford), though indefinite as 

 regards the length and continuity of the spiral fibres, show at least there is a common 

 type of structure prevalent among several orders of Mammalia, quite irrespective of 

 ruminating-power. 



c. The Stomach and Omenta. — The gastric viscus presents an enormous pear-shaped 

 figure, with the neck or pyloric extremity bent sharply round. The oesophagus enters 

 the stomach quite at the left and upper end; consequently the great cul-de-sac, or 

 fundus, is short, but widely rounded. It follows also that the great curvature is long, 

 and with a regular convex contour, whilst the lesser curvature is short and acutely 

 angular. The small cul-de-sac of the right extremity, or antrum pylori, furthermore, 

 is long, narrow, and directed forwards or upwards towards the diaphragm. The gastric 

 and splenic vessels and nerves pass on to the surface of the stomach, about midway 

 between the sharp angle of the lesser curvature and the cardiac orifice, and pursue 

 their course on the anterior and posterior surfaces, as has been described under the 

 vascular and nervous systems. They are large, and encompass the organ with a complete 

 ramified network. 



The size of the stomach of course varies according as it is distended or otherwise ; 

 the subjoined measurements therefore, it is to be noted, apply to the empty and 

 flattened organ. 



Extreme transverse diameter, median line drawn from the fundus 



to the antrum pylori =13^ inches. 



1 Linn. Soc. Journ. (Zool.) vol. iii. 1865, pp. 53-61, tab. 3. 



- Lecons, 2nd ed. tome iv. p. 16. 3 Anat. Comp. vol. viii. p. 688. 



