_Rostral Latera_, small, gradually widening from the umbo to the opposite end, which is obliquely rounded. _Infra-median Latera_, approaching to diamond-shaped, placed obliquely to the longer axis of the capitulum; or the upper part may be described as spear-shaped. [56] The only valve which I have seen at all like this, is a fossil specimen from the Upper Chalk of Scania; this is described in my memoir on the Fossil Lepadidæ (Palæontographical Society), under the name of _Scalpellum solidulum_ (Tab. 1, fig. 8, _e_, _f_), and is perhaps erroneously there considered as a carinal latus. _Carinal Latera_: these appear as if formed of two valves united together; the upper portion, widening as it ascends in a curved line, terminates in a rounded margin, which enters the deep notch in the upper latera; the other and lower portion is shorter, and terminates in a square margin abutting against the infra-median latera; the umbones of the carinal latera project beyond the line of the carina. _Direction of the Lines of Growth in the Valves._--This should always be carefully observed, on account of the great diversity there is in this respect between the different species, especially when the recent are compared with the older fossil species; moreover one of the chief characters between the genus Scalpellum and Pollicipes, depends on the direction of the lines of growth. In the scuta, terga, rostrum, and upper latera of the present species, the chief growth is downwards; in the carina, in mature specimens, it is both upwards and downwards; in the carinal latera, both upwards and towards the infra-median latera; in the infra-median latera chiefly upwards; and, lastly, in the rostral latera, towards the infra-median latera. _Peduncle_, short, not half as long as the capitulum; calcareous scales imbricated as usual, tinged red, almost crescent-shaped, acuminated at both ends, of remarkable length, so that in each whorl there are only four scales: a full-sized scale equals in length one of the rostral latera. The tips of two scales, in one whorl, lie under the middle points of the carina and rostrum; and in the whorl, both above and below, a single much curved scale occupies this same medial position. The peduncle does not seem to have been attached in any definite position to the horny coralline, as is the case with _S. vulgare_. Length of capitulum in the largest specimen .2 of an inch. The _Mouth_ is directed towards the ventral surface of the thorax. The _Labrum_ is far removed from the adductor muscle, with the upper part forming an overhanging projection; I believe there are some very minute bead-like teeth on the crest. _Palpi_, small, narrow, thinly clothed with bristles. _Mandibles_, with three teeth, of which the first is distant from the second; inferior angle not much acuminated, pectinated on both edges.