The _Palpi_ (Pl. 26, fig. 6) differ little, except in size, in the different genera, being squarish, more or less elongated, or even approaching to club-shaped: in most of the Balaninæ they are larger even than the mandibles, of which they normally form a part. Their upper margins, especially towards their free extremities, are always thickly clothed with spines; and there is generally a single row, either short (_r_) or long, of spines of greater length, which arise from a little above, and stand almost in a parallel line to, the basal margin. On the internal surface, there is sometimes a row (_t_) of very short little spines, which overhang the crest of the labrum. The _Mandibles_ (Pl. 26, fig. 5) have from three to five teeth; the lower point or angle is generally pectinated. In Coronula and its close allies, there are some small teeth intermediate between the four or five main teeth; and in these genera, though members of the sub-family Balaninæ, the lower teeth exhibit only rudiments of being laterally double.[33] The _Maxillæ_ sometimes have a notch under the upper large pair of spines, and in _Octomeris brunnea_ there is a double notch: in many species of Balanus, the inferior corner stands up like a step (Pl. 26, fig. 7, _a_): in many other genera and species, the whole edge is straight. In all, or almost all cases, the row of spines on the middle portion is double. The _Outer Maxillæ_ are always bilobed on their inner faces, and are clothed with bristles. On all the gnathites, the bristles are often doubly serrated. [33] M. Martin St. Ange describes, in his 'Mémoire sur l'Organisation des Cirripèdes,' pp. 15 and 32, "_une petite langue_" in the mouth of Lepas; but I may venture to assert that such does not exist; it is merely the point of union between the outer maxillæ. M. St. Ange, in his comparison of the mouth of Lepas with that of Phyllosoma, compares the mandible of the latter with the palpus of Lepas; the first maxilla of Phyllosoma with the mandible of Lepas; and so on with the other gnathites.