TESTACEOUS FISHES. 



695 



grow bigger, and thus to enlarge its apart- 

 ment. 



The seeming uafitness, however, of this 

 animal for penetrating into rocks, and there 

 forming an habitation, has induced many 

 philosophers to suppose that they entered 

 the rock while it was yet in a soft state, and 

 from the petrifying quality of the water, that 

 the whole rock afterwards hardened round 

 them by degrees. Thus any penetrating 

 quality, it was thought, was unjustly ascribed 

 to them, as they only bored into a soft sub- 

 stance, that was hardened by time. This 

 opinion, however, has been confuted, in a 

 very satisfactory manner, by Doctor Bohads, 

 who observed, that many of the pillars of the 

 temple of Serapis at Puteoli were penetrated 

 by these animals. From thence he very 

 jnsily concludes, that the pholas must have 

 pierced into them since they were erected ; 

 for no workmen would have laboured a pillar 

 into form, if it had been honey-combed by 

 worms in the quarry. In short, there can be 

 no doubt but that the pillars were perfectly 

 sound when erected ; and that the pholades 

 have attacked them, during that time in 

 which they continued buried under water. 

 by means of the earthquake that swallowed 

 up the city." 



From hence it appears, that, in all nature, 

 there is not a greater instanceof perseverance 

 and patience than what this animal is seen 

 to exhibit. Furnished with the bluntest and 

 softest auger, by slow successive applications, 

 it effects what other animals arc incapable of 

 performing by force; penetrating the hardest 

 bo lies only with its tongue. When, while 

 yet naked and very small, it has effected an 

 entrance, and has buried its body in the 

 stone, it there continues for life at its ease; 

 the sea-water that enters at the little aper- 

 ture supplying it with luxurious plenty. 

 When the animal has taken too great a quan- 

 tity of water, it is seen to spurt it out of its 

 hole with some violence. Upon this seem- 

 ingly thin diet, it quickly grows larger, and 

 soon finds itself inder a necessity of enlarg- 

 ing its habitation and its shell The motion 

 of the pholas is slow beyond conception; its 



Bohadsch de Animalibus Marinis, p. 153, 



progress keeps pace with the growth of its 

 body; and, in proportion as it becomes lar- 

 ger, it makes its way farther into the rock. 

 When it has got a certain way in, it then 

 turns from its former direction, and hollows 

 downward ; till, at last, when its habitation 

 is completed, the whole apartment resembles 

 the hole of a tobacco pipe ; the hole in the 

 shank being that by which the animal enter- 

 ed. 



Thus immured, the pholas lives in dark- 

 ness, indolence, and plenty; it never removes 

 from the narrow mansion into which it has 

 penetrated ; and seems perfectly content 

 with being enclosed in its own sepulchre. 

 The influx of the sea-water, that enters by its 

 little gallery, satisfies all its wants; and, with- 

 out any other food, it is found to grow from 

 seven to eight inches long, and thick in pro- 

 portion. 



But they are not supplied only with their 

 rocky habitation; they have also a shell to 

 protect them : this shell grows upon them in 

 the body of the rock, and seems a very un- 

 necessary addition to their defence, which 

 they have procured themselves by art. 

 These shells take different forms, and are 

 often composed of a different number of 

 valves: sometimes six ; sometimes but three; 

 sometimes the shell resembles a tube with 

 holes at either end, one for the mouth, and 

 the other for voiding the excrements. 



Yet the pholas, thus shut up, is not so soli- 

 tary an animal as it would at first appear ; for 

 though it is immured in its hole without egress, 

 though it is impossible for the animal, grown 

 to a great size, to get out by the way it made 

 in, yet many of this kind often meet in the 

 heart of the rock, and, like miners in a siege, 

 who sometimes cross each other's galleries, 

 they frequently break in upon each other's 

 retreats. Whether their thus meeting be the 

 work of accident or of choice, few can take 

 upon them to determine : certain it is, they 

 are most commonly found in numbers in 

 the same rock ; and sometimes above twenty 

 are discovered within a few inches of each 

 other. 



A to the rest, this animnl is found in 

 greaiest numbers at Ancona. in Italy ; il is 

 found along the shores of Normandy and 



