SHIP-WORM. 337 



nautilus. The animal is also indistinctly allied to the cuttle-fish 

 tribe j having an oval body, with the front or central part fur. 

 uished with a parrot-shaped beak, and surrounded by arms or ten- 

 tacula ; but they differ from those of the sepiae or cuttles, in being 

 very short, extremely numerous, disposed in several concentric rows 

 or circles, and not beset with any visible suckers. From above the 

 neck, or round the upper part of the head, rises a large, concave 

 flap or hood, beset on the inside with numerous but small suckers, 

 or concave tubercles. By the elevation and expansion of this con- 

 cave flap, or hood, the animal of the pearly nautilus is supposed to 

 sail. It is of a pale reddish-purple colour, with deeper spots and 

 variegations. 



[Shazo. 



Ship- Worm, 

 Teredo Navalis Linn. 



This is long a worm, covered with a calcareous shell ; the shell is 

 smooth, thin, cylindrical, more or less twisted, rather obtuse at the 

 hip ; from four to six inches in length. The same worm is not un 

 frequently found naked, or destitute of its shell, and is then called 

 Terebella, or naked ship-worm ; it has the same habits as the Te- 

 redo, and pierces planks nearly as readily. The ship.worm is a 

 native of the Indian Seas, from whence it has been imported into 

 Europe. It penetrates easily into the stoutest oak-plank, and pro- 

 duces dreadful destruction to the ships, by the holes it makes in their 

 sides ; and it is to avoid the effects of this insect that vessels require 

 sheathing. 



The head of this creature is well prepared by nature for the hard 

 offices which it has to undergo; being coated with a strong armour, 

 and furnished with a mouth like that of the leech, by which it pierces 

 wood as that animal does the skin. A little above this it has two 

 horns, which seem a kind of continuation of the shell ; the neck is 

 as strongly provided for the service of the creature as the head, 

 being furnished with several strong muscles ; the rest of the body is 

 only covered by a very thin and transparent skin, through which the 

 motion of the intestines is plainly seen by the naked eye j and by 

 means of the microscope several other very remarkable particulars 

 become visible there. This creature is wonderfully minute when 



