REPORT ON THE NUDIBRANCHIATA. 
135 
small furrows ; the inner and upper surface is smaller and fastened to the oesophagus ; the 
inner, lower surface is large, and attached to the large ampulla of the glandula hastatoria. 
The salivary ducts (fig. 27) are rather short (3 mm. long) and open into the pharynx. 
The oesophagus is strong and rather wide (PI. V. fig. 27, cl ; PI. YI. fig. 6, h), and passes 
obliquely to the left and then downwards ; when fully extended it measures 3 '5 cm., with a 
diameter of 4 '5 mm. in the anterior part, and 1*5 mm. in the posterior; the interior has 
numerous folds, which are prolonged into the upper part of the stomach. The first 
stomach (PI. YI. figs. 6, e, 7, e) is short and pear-shaped, about 11 mm. long by 9 '5 mm. in 
diameter ; it is yellowish in colour, with a thin wall not more than *4 mm. thick, but 
with stronger circular bundles ; the inside is covered with fine longitudinal folds, which 
usually bear very .fine tubercles; the opening into the oesophagus and into the anterior 
(fig. 6, c) and inferior (fig. 6, cl) hepatic duct, is round, with fine folds. The second stomach 
(figs. 6,/, 7,/; PI. Y. fig. 27) lies obliquely from above downwards and to the right ; it is 
15 ’5 mm. broad and about 7‘5 mm. long in the middle, and at the ends 9 mm., with a 
thickness of 9 mm. ; this masticatory stomach is somewhat compressed above, rounded 
and flattened, the lower end also rounded, the hinder end deeply cleft (PI. VI. fig. 6) ; the 
median and largest portion of both flattened sides is occupied by a large tendinous patch, 
almost hour-glass shaped, of the ordinary bluish-white nacreous appearance; this stomach is 
marked off from the first stomach by a circular furrow, deeper above ; a tendinous cord, 
broader at its two extremities, joins (fig. 6) the upper end of the second stomach with the 
third stomach. At the middle of the sides of the organ, where the tendinous patch is, the 
thickness of the wall is • 5 mm., at the ends they are (fig. 8) 6-6'5 mm. thick ; in front the 
cavity of the masticatory stomach is connected with the first stomach by a wide oval 
aperture, the margin of which projects slightly into the interior of that first stomach ; 
behind and above there is a small recess (fig. 8, h), which is prolonged and opens by a wide 
aperture into the posterior bile duct. The inside of the masticatory stomach behind (fig. 8,6) 
and in front (fig. 8, a) has longitudinal folds, but is smooth in the middle portion, on account 
of the thicker, somewhat uneven, yellowish cuticle. This cuticle was traversed by longi- 
tudinal furrows, and here and there by transverse furrows, which, by their intersection, mark 
off small longish, slightly- raised tubercles (PI. Y. fig. 23). When these thickened portions 
were cut through perpendicularly, the wall beneath this (‘4 mm. thick) cuticula (PI. VI. 
figs. 8, 9) and the epithelium attached to it, was seen to be composed of alternate layers 
of longitudinal and perpendicular muscle-fibres, which were easily separated from each 
other. On longitudinal section (fig. 8) they showed about six longitudinal bands, whitish, 
with a tendinous glitter, 1 which, however, do not reach from one end to the other ; these 
longitudinal bands are composed of a number of longitudinally running fibres ; they are 
separated from each other by short, perpendicular fibres of greyish -yellow colour. On trans- 
1 The above-mentioned small species ( Onchidium palaense, S.) had a similar structure, and about the same number 
of bands (6). 
