100 ZOOLOGY. 



conical and granular feet, decreasing in size from the middle of the body 

 towards each end, and having short bristles at their extremity ; no cirri, 

 gills, nor similar appendages. The head is distinct, with two stout annulate 

 antennjB, and the mouth has a pair of corneous jaws. Peripatus juliformis 

 of Guilding, from which the characters are taken, is three inches long, dark 

 brown, annulated with yellow, the dorsal line black ; and it has thirty feet 

 on each side. Lacordaire found a specimen in Cayenne, sunk in the mud 

 at the margin of a river, and Goudot found another species near Table 

 Mountain in South Africa, under a stone in a shady place. The nervous 

 system differs from that of the other annelida in- being bilateral (somewhat 

 as in Malacobdella) ; and on this account, Gervais is of opinion that it 

 forms the type of a distinct group of worms, whilst Milne Edwards, 

 who discovered this peculiarity, considers it as indicating a passage to 

 Nemertes. See Kirby's Bridgewater Treatise, p. 259, pi. 8, fig. 1, 2. 



Fam. 7. ChcetojJteridce. The genus Chcetopterus was formed by Cuvier 

 for a worm from the Antilles, eight or ten inches long, inhabiting a tube of 

 a i^archment-like consistence, whence its name Ch. pergamentacerus. 

 There are neither rostrum, jaws, nor a proper head. There is a lip with 

 two rudimentary antennte, followed by a disk with eight or nine pair of feet, 

 succeeded on each side by a wing-like projection, bearing bristles. The 

 branchise are medial, and in the form of laminae ; posterior extremity with 

 numerous lateral feet. 



Fam. 8. Arenicolidce. In Arenicola the body is cylindrical, composed of 

 a moderate number of segments subdivided by numerous wrinkles. The 

 head is rudimentary, with a small terminal rostrum ; no jaws, eyes, antennae, 

 nor cirri. The feet have two branches, and are armed with simple and 

 armed bristles ; branchiae in bunches divided like the branches of a tree, and 

 arranged in pairs along the middle portion of the body, numbering from 

 thirteen to twenty pair. They burrow in the sand about low water mark, 

 and are extensively used by fishermen as a favorite bait for marine fish. 

 A. j)iscatorum is eight or ten inches long. 



Okder 3. Cepiialobkanchia (or Tubicola). These sedentary annelida 

 live in calcareous, sandy, or membranaceous tubes ; the soft appendages 

 are generally confined to the anterior extremity ; the head is indistinct, 

 without eyes, rostrum, or jaws ; the branchise are plumose, and situated at 

 the anterior extremity [pi. ^^^fig. 68). They comj^rise the two families 

 Serptdidm and Aw.pliitritidcB. The former is distinguished from the latter 

 by having the branchial plumes separated into two masses by a pedunculated 

 operculum, or covered by a solid one when withdrawn w^ithin the shell. 



Fam. 1. Serpididce. The genus Serpula {pi. 75, fig. 70) has the body 

 tapering posteriorly, the mouth terminal, and surrounded with a crown of 

 long, feathery, and often finely colored branchiae, which give the animal the 

 appearance of a zoophyte. These are used in taking the small living cbjects 

 upon which they feed. The feet are lateral, the seven anterior pair attached 

 to a membranous base. The part bearing these feet forms a kind of thorax 

 distinguishable from the remaining part of the body. From the internal 

 bas3 of each of the two masses of branchiae a filament arises, one of which 

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