NOTES ON THE NATURAL HISTORY OF THE BELL ROCK. 107 



Darwin computed that some " ribbons " contained as many as 

 six hundred thousand eggs. The acorn barnacles which have 

 escaped the voracity of the white whelks have in some places 

 attained a height of two inches. On examination, each shelly 

 casement is seen charged with spawn, which, later on, will be 

 liberated as free swimmers, totally unlike the parent form, to 

 enjoy a brief period of unrestricted freedom before settling 

 down on the Rock surface, or, for that matter, any immersed 

 object that comes handy, and ultimately assuming the adult 

 form. The young swimmer, feeling itself gradually becoming 

 invested with a shelly covering, casts about for a suitable site 

 to pass the remainder of its existence. Selecting the Rock 

 surface, it attaches itself by its head, the antennae become 

 cemented to the surface, the eyes remain in a rudimentary 

 form, the shelly plates which latterly form the door of its 

 domicile appear, a few more pairs of legs are developed, and 

 by a series of frequent moultings (like other crustaceans) 

 arrives at the perfect state. The bunches of " fingers " which 

 we see this animal protrude and withdraw when under water 

 are in reality its feet, of which there are twelve pairs, the 

 rhythmic expansion and contraction of which induce a current 

 in the water attracting to its mouth the minute objects upon 

 which it feeds, thus giving rise to the saying that this animal 

 stands on its head and literally kicks its food into its mouth. 

 In all other Crustacea the sexes are distinct, the barnacles 

 alone having the peculiarity of being bi-sexual, or having 

 both sexes united in the same individual. The general 

 tendency throughout nature the evolution from a lower to 

 a higher order, from the simple to the complex appears in 

 the case of the barnacle to be reversed. Gifted in the initial 

 stage of its existence with all the functions of a free-swimming 

 animal, and possessing organs which ultimately become rudi- 

 mentary, the final phase in which all power of volition is lost, 

 certainly does not appear one of progression. 



Hermit crabs are at present abundant, and also demon- 

 strate their wonderful fecundity. Starfishes principally the 

 five-rayed variety are now numerous, and garnish each 



