[8s]

The two end (that is, the rostral and carinal) rows of narrow scales remain to be described: those at the rostral end (fig. 8) are as high as the larger lateral scales, but only about one-fourth as wide: in shape they are almost a rectangular oblong, with their upper ends a little rounded, and the outer (with respect to the longitudinal axis of the animal) basal angle a little produced: hence the two lateral margins of the scales of this rostral row do not quite match each other; consequently, to make the animal symmetrical, there must have been a corresponding approximate row of small scales on the other side of the medial line. The straight inner (both sides of the peduncle being supposed to be present) edges of the scales of the row just described, extend rather beyond the occludent margin of the scuta. The scales in the carinal row, at the opposite end of the peduncle, are not above half the width of those of the rostral row: they are of nearly the same shape, but their upper ends are more pointed, and their outer (with respect to the medial longitudinal axis of the animal) basal angles more produced; their straight inner margins projected considerably beyond the carinal edge of the second latera: it is more obvious in this case than in the rostral row, that there must have been a second adjoining row of small scales on the other side of the carinal medial line. The small scales of the carinal and rostral rows differ from the others in their inner (that is, close to the medial axis), basal angles, not crossing each other; so that the peduncle could have been divided in a medial

Growth. New scales for the peduncle are formed round its upper edge, at the bases o f the valves of the capitulum, the chief growth of which, as we have seen, is downwards: hence, we here have, as in other pedunculated Cirripedia, a principal line of growth round the summit of the peduncle. It can be seen that a new scale is first formed under the second la tus, at the carinal end of the peduncle; and this agrees with the fact that there is one more scale in this row than in that next to it; and one more in the latter, than in the row under the scutum. I may mention, as in conformity with this fact, that in the development of the young of Scalpellum vulgare from the larval condition, the calcareous scales on the peduncle first appear under the carina.