80 



TRILOBITES. CIRRHOPODA. 



coasts. On some parts of the coast of New Jersey they form 

 an article of food for swine. 



20. The En'tomos'tracans (from the Greek, entomos, incised, 

 and ostrakan, a shell) are all extremely small, and most of them 

 have a single eye placed in the middle of the front part of the 

 animal. They abound in fresh waters. 



21. To the class of Crusla'ceans also belong the Tri'lobites, a 

 tribe of extinct animals found only in the fossil state^ they would 

 bear some resemblance to a very large oniscus or sea-louse, if the 

 body of the latter were divided into three lobes by longitudinal 

 grooves. Three species of trilobiles are figured below (fig. 69). 



Asaphus Caudatus. 



Asaphus Buchii. 

 Fig. 69. 



Colytnene Blumenbachii 



CLASS OF CIRRHOPODA OR CIRRIPEDA. 



"However distinct in outward appearance, and even in their 

 internal economy, the creatures composing the primary divisions 

 of animated nature may seem to be when superficially examined, 

 closer investigation invariably reveals to the zoologist gradations 

 of structure connecting most dissimilar types of organization, 

 and leading so insensibly from one to another, that the precise 

 boundary line is not always easily defined. The Cirrhopods or 

 Barnacles present a remarkable exemplification of this important 

 fact." 



22. The class of Cirrhopoda (from the Greek, kirros,a cirrus 

 or curl, and pous, foot) is composed of animals, which, in many 

 respects, especially as to their shells, resemble mollusks, but are 



20. What are en'tomos'tracans ? 



21. What are tri'lobites ? 



22. What are Cirrhopods ? How are they characterized ? 



