A Monograph on the Sub-class Cirripedia (Volume 1 of 2): The Lepadidae; Or, Pedunculated CirripedesDarwin, Charles
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A Monograph on the Sub-class Cirripedia (Volume 1 of 2): The Lepadidae; Or, Pedunculated Cirripedes
Darwin, Charles
Cirripedia; Lepadidae
_L. scutis terga angustè obtegentibus: carinæ cristâ internâ tenui in
parte superiore positâ: rostro conspicuo, squamarum sex subjacentium
latitudinem æquante: lateribus, superficie internâ triangulâ, squamarum
septem subjacentium latitudinem æquantibus._
Scuta narrowly overlapping the terga: carina with a slight central
internal ridge in the upper part: rostrum conspicuous, as wide as six of
the subjacent scales: latera, with their internal surfaces triangular,
as wide as seven of the subjacent scales.
Palpi square at their ends: mandibles with twice as many pectinations
between the first and second main teeth, as between the second and
third: maxillæ slightly notched, with the inferior angle slightly
prominent: caudal appendages more than twice as long as the pedicels of
the sixth cirrus.
Timor; Brit. Mus., (given by Cuvier to Leach); Nicobar Islands,
according to Reinhardt.
Capitulum as in _L. dorsalis_. The teeth on the prominent rims of the
valves are small and approximate; but the specimen was much worn.
_Scuta_, triangular, slightly overlapping the terga; the line of
junction between these valves slightly sinuous, the upper part of the
tergal margin of the scuta being slightly hollowed out, and the
corresponding upper portion of the margin of the terga being slightly
protuberant. Internally, there is a considerable depression for the
adductor muscle; and besides the usual knob at the rostral angle, there
is a trace of a knob at the baso-tergal angle.
_Terga_, as seen internally, irregularly rhomboidal, ending downwards in
a blunt point, of which the two sides, (neither being sensibly hollowed
out,) stand at about an angle of 45° to each other. Scutal margin, with
the upper part, (as above remarked,) slightly protuberant: near the
bottom of this margin, there is a very slight projection, answering to
the small knob at the baso-tergal angle of the scutum. Externally,
towards the basal angle, the narrow strip not concealed by the
overlapping of the latera and carina is square-edged, with the zones of
growth on it straight.
_Carina_, internally concave in the upper free part, with a slight,
central, internal crest, caused by the projection of each successive
zone of growth. The inner growing surface is almost pentagonal in
outline; with the basal margin square and truncated in the middle.
_Rostrum_ (fig. 2 _a_), rather conspicuous, many zones of growth being
preserved. It equals in width six of the subjacent scales of the
peduncle, but as these are rather smaller than elsewhere, the width
equals about five of the ordinary uppermost scales; compared with the
latera, it is nearly 5/7ths of their width.
_Latera_, unusually large; as seen on their interior surfaces, (or in a
section parallel to the zones of growth,) they are triangular, elongated
transversely, with the carinal angle a rectangle. In width they equal
the seven subjacent scales of the peduncle, and are more than half as
long as the basal margin of the carina.
Public-domain text, read in full here on John Shaqi.
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