AND PHARYNX OF THE SCORPION 397 
delicate, short, and widened posteriorly, so as to resemble what M. 
Léon Dufour calls the ‘jabot’ in insects. The cesophagus is held 
upon each side, towards its middle, by a fine muscular band directed 
backwards, and towards its point of union with the stomach by a 
similar band directed forwards. These muscles are attached to the 
sternal floor, formed, as is known, by the basilar pieces of the 
appendages. They serve to stretch the cesophagus either forwards or 
backwards, so as to facilitate deglutition. 
“ The walls of the cesophagus are thin and smooth internally, and 
present a few fine folds.” 
In the figures (of. czz., pl. iv, figs. 1 and 6), which represent the 
anterior part of the alimentary canal, the cesophagus is represented as 
a straight, taper tube, ending in the mouth, without change of 
direction. 
At page 32, M. Blanchard states, under the head of— 
“ Muscles o7 the buccal appendage—We have indicated the two, 
long, diverging, apodemes of this piece (p. 19). Upon the base of 
each of them is inserted an elevator muscle, provided with two fixed 
attachments to the cephalo-thoracic shield in front of and external to 
the median eyes (pl. ii, fig. 4 ee and fig. 6 a). By its contraction, this 
muscle causes the buccal appendage to be elevated a little—a move- 
ment which takes place when the animal introduces food into its 
mouth. A transverse muscle is attached to the two apodemic plates 
(pl. ii. fig. 4.7); it is this muscle which, acting either on the one side 
or on the other, determines the slight lateral movements of the buccal 
appendage. It is to be observed, that this piece, solidly fixed 
between the foot-jaws, sensibly involves the latter during the execu- 
tion of its slight movements.” 
The structure of the parts which I have observed ina large species 
of Buthus may be described as follows : 
The “buccal appendage” of M. Blanchard is a_ vertically 
elongated, laterally compressed, cushion-like prominence, broad and 
rounded above, where it is marked by a slight median ridge, slightly 
concave from above downwards in front, and narrowed below 
(Pl. XII, figs. 1, 2, 3 4). Its anterior and lateral surfaces are covered 
with fine, short hairs, which form a projecting pencil at its anterior 
inferior angle. There is no aperture whatsoever above this body, 
between the chelicerze ; but, below and behind it, the aperture of the 
mouth, large enough to admit the head of a fine needle, can be very 
easily found. I entertain no doubt, therefore, that this “buccal 
appendage” is a true labrum, and, indeed, in all essential respects, it 
is exactly like that part in the craustacea. 
