ight difference in the
carina, and again some dissimilarity in habits.

_Description._--The valves, as just stated, generally resemble those of
_L. truncata_; scarcely any appreciable difference can be detected in
the scuta; the apex, however, of the inner surface seems coloured a
darker purple. The terga, as seen from vertically above (Pl. VIII, fig.
5 _b_), have a fold or indentation on the upper or occludent margin, as
large and as conspicuous as that receiving the margin of the scuta: this
fold, as seen on the inner corium-covered surface (fig. 5 _a_), descends
below the roughened knob at the upper angle of the carinal margin, which
is not the case with the slight fold in the same place in _L. truncata_;
its presence seems caused by the edge of the central internal crest, in
the upper part of the carina, being square (instead of round, as in _L.
truncata_), and thus more deeply affecting the outline of the terga,
between which it is inserted. The upper part of the scutal margin of the
terga, as seen internally (fig. 5 _a_), overlaps the scuta in a large
_rectangular_ projection. From the depth of the two opposite folds,
namely, that caused by the tergal edge of the scuta and that by the
crest of the carina, the inner face of the tergum is divided into two
almost equal areas. The carina has its central crest square (fig. 5 _c_,
_d_,) instead of being rounded as in _L. truncata_. The inner growing or
corium-covered face is nearly at right angles to the longitudinal axis
of the whole valve, instead of being oblique to it; it is convex or
protuberant, with a central raised line, and two little knobs on each
side of the upper part; the two lateral margins are slightly hollowed
out, and the basal margin is not highly protuberant. The rostrum is
excessively minute, barely above 1/200th of an inch in width; it is a
little enlarged at each zone of growth. Latera lost; no doubt they were
rudimentary.

A fragment of a posterior cirrus, which adhered to one of the valves,
shows that each segment supported four pairs of spines.

Width of the capitulum before disarticulation, probably was about 1/10th
of an inch.

* * * * *

_Species mihi non satis notae, aut dubiae._

ANATIFA VILLOSA. _Brugiere._ Encyclop. Meth. Des. Vers., tom. i,
1789, p. 62, Pl. clxvi.

On ships: Mediterranean.

ANATIFA HIRSUTA[69] _Conrad._ Journal of the Acad. of Nat. Sc.,
Philadelphia, vol. v