MOLLUSCA. 11 



CLASS CIRRIPEDES, LAM. 



The Cirripedes are so called from their arms or tentacles, 

 which are curled up like a lock of hair, and with which they seize 

 their prey. It is the group of animals which inhabit the shells 

 commonly called barnacles. 



These shells are all fixed, either directly or indirectly to some 

 foreign body. To compensate for this relative immobility, they 

 usually attach themselves to locomotive or floating objects, such 

 as drift wood, vessels' bottoms, fishes, lobsters, &c. Many of 

 them are, therefore, extensive voyagers, and hail from no particu- 

 lar sea. During the last summer, two vessels lay side by side at 

 one of our wharves, one from India, the other from Sweden, arid 

 their bottoms were occupied by similar species of barnacles. 

 In long voyages, especially in warm climates, and still more cer- 

 tainly where vessels are not sheathed with copper, the barnacles 

 adhere in incredible numbers, and grow to such a size, as materially 

 to impede the course of the vessel. Conveyed in this way, they 

 are brought in contact with their food, and are seen in every port. 

 Other barnacles adhere to stones, piles, and similar immovable 

 objects, and are entirely dependent for their food upon such ob- 

 jects as the passing current brings within the reach of their arms. 



They have several pairs of arms or tentacles, which they can coil 

 up within their shell, or protrude, at pleas- 

 ure. Each of the arms is double, and 

 their edges are garnished with a kind of 

 fringe, so that they appear somewhat like 

 small feathers. When covered by water, 

 for they are sometimes left by the tide, 

 their arms are in constant motion, and re- 

 mind one of the spread human hand grasp- 

 ing at something in space, a musquito, for 

 instance. This grasping motion is regular, 

 at the rate of 80 or 100 times in a minute. 



Nature has also provided that these sedentary animals may be 

 widely diffused. Eggs are discharged by the parent in great num- 

 bers, which soon produce little animals very different in shape 



