136 
THE VOYAGE OF H.M.S. CHALLENGER. 
verse section these last (fig. 9) appeared as yellowish-white longitudinally striated lamellae, 
which at either end unite into a common muscular mass ; between these lie greyish-white 
perpendicularly striated lamellae, the same which in longitudinal section are tendinous- 
glittering white. The white hue of these lamellae is the optical expression of sections 
which follow the direction of the lamellae. The wall of the stomach consists in 
this way of layers of muscular fibres, which are made up of thin strands lying in close 
proximity ; the layers alternate in direction, and are, therefore, quite different in longi- 
tudinal and transverse section. In the periphery of the organ the layers unite into a 
very thick, tight covering, which contains abundant blood-vessels (fig.. 8). To the right 
hand and above in the first stomach (which may be regarded as an antechamber to the 
masticatory stomach) is the wide obliquely-oval orifice of the third stomach, the lamellae 
of which are very conspicuous in the depth of the orifice ; the hinder margin of the 
opening is more conspicuous, and projects in the form of a fold with transverse furrows. 
The third, the lamellated stomach (fig. 6, h) is united by a short neck with the first stomach ; 
it is of a rounded angular contour, somewhat flattened, of about 1 1 mm. diameter by about 
6 mm. in height ; it is radially striped with a blackish colour, the folds of the inside are 
visible from the outside, especially at the margins. Besides the above-mentioned liga- 
ments between this and the second stomach, there are also two strong bands on the upper 
surface, the exact relations of which could not be made out. The walls of the third 
stomach are not thick : the inside has numerous yellowish-white variously-sized folds 
passing from above downwards, which at the lower end reach a height of quite 3 mm. 
Generally a high fold alternates with several quite low ones ; the largest folds are pro- 
vided at the sides with smaller longitudinal folds directed upwards (PI. Y. figs. 21, 22). 
All the folds converge after the middle point of the stomach, and leave a fine central 
space. Below the folds are much lower in the opening of the stomach ; above they 
gradually decrease in size as far as the intestine, where they end rather abruptly. The 
intestine (PI. VI. fig. 6, ih) takes its rise at the upper end of the third stomach, and runs 
forwards for a short space (12 mm.), and then bends to the right, and ascending along 
the right side of the body, traverses a more or less superficial furrow upon the liver 
(PI. V. fig. 27, ee), winding forwards and backwards ; in the region of the middle of the 
pericardium it descends, bending backwards, and runs beneath the pericardium along the 
under side of the mucous gland, and approaching the middle of the body it takes its course 
between the foot and the lung-sac to the anal papilla (PL V. fig. 2). The length of 
the whole intestine is 14 cm. with an average breadth of l’5-2'5 mm. ; only the first 
extent of 6 mm. was somewhat broader, about 3 ‘5 mm. in diameter, widened into an 
ampulla 1 (PL YI. fig. 6, i), showing on its outside a number of black pigmented lines. 
The inside of the intestine is yellowish-white in colour, and furnished throughout its 
entire length with fine longitudinal folds, which are a trifle higher in the ampulla, and 
1 This ampulla is regarded by Cuvier as a special stomach (Mem. sur l’Onchidie, p. 8, pi. figs. 5y, 7 y). 
