74 CONCHOLOGIST’S COMPANION. 
confidence in him. A kind of crab, naked like the 
hermit, and very quick-sighted, is the constant 
companion of the Pinna Marina. They live and 
lodge together in the same shell, which belongs to 
the latter. When the Pinna has occasion to eat, 
he opens his valves, and sends out his faithful 
purveyor to procure food. If any foe approaches, 
the watchful crab returns with the utmost speed and 
anxiety to his blind protector, who, being thus 
warned of danger, shuts his valves, and escapes the 
rage of the enemy; when, on the contrary, the crab 
loads himself with booty, he makes a gentle noise at 
the opening of the shell, which is closed during 
his absence, and when admitted, the two friends 
feast together on the fruits of his industry.* This 
curious fact, although well known to the ancients, 
escaped till lately the observation of the moderns. 
Aristotle tells us, that the Pinna kept a guard to 
watch for him; that there grew to the mouth of the 
Pinna a small animal, having claws, and serving as 
a caterer, resembling a crab, and termed the Pinno- 
phylax. In like manner, Pliny mentions a small 
animal, called Pinnotheres, which, he says, is liable 
to injury, and therefore prudently hides itself in the 
shell of oysters. He also speaks of the Pinna as 
belonging to a genus of shell-fish, produced in muddy 
water, and constantly attended by a companion. 
* Hasselquist. 
