TKIDACNID^B. 



330 



by broad sides bristling with white scales. The hinges have two 

 teeth ; the ligament is elongated and external. 



The animal of Tridacna is remarkable for its fine colours. Tridacna 

 safrana is of a beautiful blue round the edges, rayed through a 

 shade of very pale blue. More in the interior is a row of small moons 

 of a yellowish green ; the centre is a bright violet, with brownish 

 longitudinal punctured lines. " We have at this moment before our 

 eyes," say the travellers Quoy and Gaimard, " one of the most charming 

 spectacles that can be seen, when at a little depth beneath the 

 surface a number of these animals display the brilliant velvety colours 

 and varying shades of their submarine parterres. As we can only 

 perceive the gaping opening of the valves, we may imagine to our- 

 selves what is its first aspect." The mantle of the animal is closed 

 and ample ; its edges are swollen, and reunited in nearly its whole 

 circumference in such a man- 

 ner as to leave only three 

 very small openings two in 

 the upper part ; the one serves 

 the purpose of discharging the 

 products of digestion, the other 

 gives entrance and exit to the 

 water necessary for respiratory 

 purposes. The third opening 

 is in the lower part of the body, 

 and free ; it leaves an opening 

 for the passage of the foot, 

 which is enormous, and is 

 surrounded with an ample tuft 

 of byssoidal fibres. 



Aided by this silky tuft, the 

 animal attaches itself to the 

 rocks, and suspends its weighty 

 shell from them. If it is in- 

 tended to remove those attached 

 to the sides of the rock, it is 

 necessary to cut the cords of the tendonous byssus, by which it is held 

 suspended, with a hatchet. 



All the species are inhabitants of the Tropical seas. The Tridacna 



z 2 



Fig, 149. Tridacna squamosa (Lamarck). 



Fig. 150. Tridacna squamosa, on the inside (Lamarck). 



