erate regions. The _S.
vulgare_ ranges from the Norwegian seas to Naples. Most of the
species are inhabitants of deep water.

_Affinities._--In the preliminary remarks, we have seen how this genus
blends into Pollicipes; and under the head of Oxynaspis, I have shown
its close affinity to that genus. If, indeed, we take _Pollicipes
spinosus_, and destroy all but six of the already minute and almost
rudimentary latera, we shall, as far as the capitulum is concerned,
convert it into a Scalpellum, closely similar to _S. villosum_. If we
take any species of Scalpellum, (excepting _S. villosum_ and _S.
rutilum_,) and destroy all the valves, but the scuta, terga and carina,
we shall convert it into an Oxynaspis. Lastly, I have shown under Ibla,
that in several most remarkable peculiarities of structure, there is a
manifest affinity between Scalpellum and that genus.

_Geological History._--Full details on this subject have been given in
the Memoirs of the Palaeontographical Society. I will here only state,
that the oldest known form of Scalpellum occurs in the Lower Green Sand.

[=T= SUB-CARINA NULLA.]

1. SCALPELLUM VULGARE. Pl. V, fig. 15.

SCALPELLUM VULGARE. _Leach._ Encyclop. Brit. Suppl., vol. iii,
1824.

LEPAS SCALPELLUM. _Linn._ Systema Naturae, 1767.

---- _Poli._ Test. utriusque Siciliae, Pl. vi., fig. 16. 1795.

POLLICIPES SCALPELLUM. _Lamarck._ An. sans Vertebres, 1818.

POLYLEPAS VULGARE. _De Blainville._ Dict. Sc. Nat., Plate, fig. 4.
1824.

SCALPELLUM LAEVE, var. _Leach._ Zoolog. Journal, vol. ii, p. 215,
1825.

---- SICILIAE, var. _Chenu._ Illust. Conch. Pl. iv, fig. 9.

SCALPELLUM VULGARE, (et var.) _Brown._ Illust. of Conch., 1844,
Pl. li., figs. 7 to 20.

_S. (Herm.) valvis 14, si rostrum paene rudimentale includatur: lateribus
superioribus inaequaliter ovatis._

(Herm.) Capitulum with 14 valves, including the rudimentary rostrum:
upper latera irregularly oval.

Mandibles, with four or five teeth: maxillae, with the edge straight,
bearing numerous spines.

COMPLEMENTAL MALE flask-formed, with four rudimentary valves; no mouth;
cirri not prehensile; attached to the occludent margin of the scutum,
near the umbo.

Great Britain, Ireland, France, Norway, Naples. Attached to
horny corallines, at from twenty to thirty, sometimes even to
fifty fathoms in depth, according to Forbes and MacAndrew.

HERMAPHRODITE.

_Descr