PROTEOLEPAS BIVINCTA. 591 



gether, — one (a) probably representing the mandibles, and 

 formed into a single large tooth ; the other (b) formed of 

 three teeth, and probably representing the outer maxillae • 

 the first-mentioned set of teeth, which seemed to me to arise 

 from between the other two sets, being the inner maxillae. 

 If this view (and it must be remembered how excessively 

 minute the parts are) be not, as I now suspect, correct, we 

 must suppose that the outer maxillae are aborted, and we 

 have seen some tendency towards this in other cirripedes ; 

 the compounded organ being formed only of the mandibles 

 (having on this view four teeth) and the inner maxillae. As 

 far as the mandibles are concerned, their existence, I may 

 remark, is plainly shown by the presence of the palpi, 

 which in all cases belong to and form part of the mandibles. 

 The ventral surface of the mouth, immediately beneath the 

 free portion of the compounded mandibular organ, consists 

 of a triangular projection, but I could see no appearances to 

 make me suppose that this part represented the outer maxillae. 

 The compound organ — in general shape, and in the oblique 

 manner in which the front part is cut off and terminates in 

 ligamentous apodeines, to which muscles are attached, — pre- 

 sents an unmistakable likeness to a mandible. It is hollow 

 within, and muscles appear to extend some way up, perhaps 

 to the transversely toothed portion, which represents, as I 

 believe, the inner maxillae : these two groups of teeth, any- 

 how, seemed to have some power of sliding over each other, 

 and altered their positions during the course of dissection. 

 On each side of the mouth, there is a muscle attached by its 

 lower end to the basal edge of the lab rum, and two others, 

 one above the other, attached by their lower ends to about 

 the middle of the labrum; these muscles, which are dis- 

 tinctly striated or voluntary, I infer, from analogy, run up 

 to the ligamentous apoclemes of the compound mandibles. 

 There appeared to be other more delicate muscles attached 

 to the basal articulation of the mouth on the ventral face, 

 and these, I presume, would run to the supposed inner 

 maxillae. 



The mouth in forming a prominence separated by a dis- 

 tinct articulation from the body, and in the union of the 

 palpi and labrum (though here carried to excess), is con- 



