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A Monograph on the Sub-class Cirripedia (Volume 2 of 2) / The Balanidæ, (or Sessile Cirripedes); the Verrucidæ, etc., etc. cover

A Monograph on the Sub-class Cirripedia (Volume 2 of 2) / The Balanidæ, (or Sessile Cirripedes); the Verrucidæ, etc., etc.

Chapter 280: PLATE 27. NERVOUS SYSTEM AND SENSES.
By Charles Darwin
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This work presents a detailed monograph on the sub-class Cirripedia, focusing on various species of barnacles, including the Balanidæ and Verrucidæ. It includes comprehensive descriptions, classifications, and illustrations of these organisms, contributing to the understanding of their biology and taxonomy. The author examines their anatomical features, reproductive habits, and ecological roles, providing insights into their adaptation and evolution. The text serves as a significant resource for naturalists and biologists interested in crustacean studies, reflecting the author's meticulous research and dedication to the field.

PLATE 27.
NERVOUS SYSTEM AND SENSES.

  • Fig. 1, Nervous system of Coronula diadema, seen from the ventral
    surface.
  • A, infra-œsophageal ganglion; two pairs of rather small nerves, arising from the dorsal surface, cannot be here shown.
  • B, supra-œsophageal ganglion, double.
  • C, ophthalmic ganglion, single.
  • D D, eyes, as believed to exist.
  • a, three pairs of nerves, running to the gnathites and olfactory pouches; a′, nerve rising from the collar, running towards the mandibles.

  • b, single medial nerve, running to the great transverse muscle, extending across the upper part of the stomach.
  • c, collar-nerve or chord, uniting the infra- and supra-œsophageal ganglions.
  • d, great splanchnic nerve, here spread laterally out, but properly running along the sides of the upper part of the prosoma, and therefore under the collar-nerve; d′, plexus by which this nerve is connected with the supra-splanchnic nerve, e.
  • e, supra-splanchnic nerve, rising from the collar, almost in contact with the supra-œsophageal ganglion; e′, small nerve rising from the end of the supra-œsophageal ganglion, and running to the adductor and surrounding muscles.
  • f, f, pair of great nerves (antennular), distributed over the sack and shell.
  • g, chord (in appearance single), uniting the supra-œsophageal ganglion with the first (C), or ophthalmic ganglion.
  • h, small medial nerve, running to near the adductor muscle.
  • i, nerve supposed to run from the ophthalmic ganglion to the eye.
  • k, small nerve, rising from the main ganglion (A), between r1 and r2, or the nerves running to the first and second pairs of cirri.
  • œ, position of the œsophagus.
  • r1 nerve entering the first cirrus.
  • r2, r3, r4, r5, r6, nerves entering the five succeeding pairs of cirri.
  • s, nerve entering the probosciformed penis.
  • 2, nervous system of Balanus tintinnabulum; letters of reference as in fig. 1.
  • 3, acoustic sack of Balanus tintinnabulum.
  • 4,””Coronula diadema.
  • 5, eye of Balanus tintinnabulum; i, nerve coming from the ophthalmic ganglion; D, eye itself.