CIRRIPEDES. 649 



strongly articulated and adapted to walking, are attached to the 

 thorax. The common name of these Crustaceans, is the King. 

 Crab or Horse-foot The first name refers to its size, the last to 

 its shape. They feed on animal substances, and are gathered as 

 food for hogs and poultry, and also used as manure. Lamarck 

 calls them giant branchiopods, in allusion to the gigantic stature 

 of Ronii'. of the species. The color is of a uniform dark brown. 

 To this order we assign the TRILOBITES, (sometimes arranged in 

 a separate order,) fossil animals, the knowledge of which is 

 limited to the shell or crust. (Plate XVI. fig 2d.) Feet have 

 not been found in connexion with their remains, so that it cannot 

 be certainly known whether or not they possessed these mem- 

 bers. Agassiz remarks, "there is an incompleteness and want 

 of development in the form of their body that strongly reminds 

 us of the embryo among the Crabs." Their food is supposed to 

 have been small water animals ; their habitat the vicinity of 

 coasts in shallow waters, where they lived gregaTiously in vast 

 numbers. We here also place Fluvicola Herricki, a singular 

 Crustaceous animal which has been found adhering to rocks in 

 and near the water of West Canada Creek. "It is detached 

 with considerable difficulty, and when so detached, partially rolls 

 itself up." (DeKay.) The locality in which they are found, is 

 noted for fossils and petrefactions ; and, as De Kay intimates, it 

 is a singular coincidence that it should furnish animals so strongly 

 resembling the extinct trilobites, see Plate XVI. (fig. 1 and 2c,) 

 which presents fi'gures of some of these animals that were found 

 in Clinton, Oneida county, N. Y., in a ravine a little North of 

 Hamilton College. They seem to be allied to the present order. 



FOURTH ORDER. CIRRIPEDES, (Lat. cirri, ringlets or tufts; 

 pedes, feet,) 



These animals were ranked by the earlier naturalists among 

 the Mollusks, and they certainly possess many characters in 

 common with rome of those animals, yet exhibit greater sym- 

 metry of form. The body is prolonged, and from each side pro- 

 ceed long and slender feet, curving together into a kind of curl, 

 whence the name Cirripedes, curl or tuft footed. They are in- 

 closed in a shell, which is more or less conical. These animals 

 are subject to a metamorphosis, the young having two valves 

 like the bivalve Mollusks, and capable of swimming about until 

 they become permanently affixed. In this state, they are able 

 to protrude the limbs from the fore part of the shell, the front 

 pair being of considerable size, and furnished with a sucker and 



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