CLASSIFICATION OF THE ANIMAL KINGDOM. 175 



corresponds throughout the entire division. All the classes possess nervous 

 ganglia, but instead of their being arranged strially in pairs, (though this 

 is somewhat the case with the Cirrhopods,) they are distributed in various 

 parts of the body. The first in order, the Cirrhopods, or Barnacles, 

 though very dissimilar in outward form to the superficial observer of the 

 articulated tribes of the Homogangliate division, yet, on close inspection, 

 will be found to bear a wonderful resemblance to them, both in their 

 internal and external structure. The common goose barnacle, for instance, 

 (Pentalasmis Vitiea,) seems from its outward shelly texture to belong to 

 the Mollusks, but remove its covering, and we have an animal intimately 

 allied in all its parts with the Crustacean class. The shell of this crea- 

 ture is composed of five distinct parts, united together by a strong 

 membrane, except along the anterior margin, where a fissure is left, 

 through which the articulated members can be protruded at pleasure. At 

 the base of the shell this same membrane is prolonged into a hollow 

 cylindrical foot-stalk, which attaches the animal to any submarine support. 

 This tube, by means of internal muscles placed longitudinally, can be bent 

 any way at the will of the animal. The oral apparatus is situated at the 

 base of the fissure spoken of before, and is provided with a rudimentary 

 apparatus of jaws, furnished with minute palpi, and three pairs of mandibles. 

 Behind the mouth are certain fleshy appendages which constitute the 

 branchial or respiratory organs. Above the mouth are six pairs of artic- 

 ulated limbs or cirrlii on each side, which are used by the animal for the 

 prehension of food; while, at the extremity of the body, we find a long 

 flexible tail-like organ, perforated by a minute aperture. The nervous 

 system also, as well as the external shape, assimilates strongly to that of 

 the Crustacea, in the Homogangliate division. It consists of a supra- 

 cesophagal mass, or brain, from which issues a chain of double ganglia, 

 arranged along- the ventral margin, and from thence nerves are distributed 

 to the cirrhi and surrounding parts. The muscular system is well devel- 

 oped, and is appropriated, says Professor Jones, "partly to the movements 

 of the shell, and partly to the general motions of the body." Their 

 food consists of entomostraca and other minute animals, caught as they 

 are swimming past, by the flexible cirrhous arms, which are alternately 

 expanded and drawn in. Their digestive apparatus consists of a mouth, 

 armed with strong lateral jaws, a short oesophagus, provided with two 

 salivary glands; a capacious stomach, surrounded with coecal appendages, 

 representing the liver; and a simple intestine placed along the dorsal 

 part of the animal, and terminating at the root of the tail-like organ 

 before spoken of, which is placed at the top of the longitudinal fissure. 

 Little seems to be known respecting the circulatory system of these 

 animals, and their respiration is effected by the branchial organs spoken of 



