Norwich Castle Museum. 117 
The Pectens, of which family our well-known 
Scallop is a member, are a numerous and widely- 
distributed race, all of them very handsome shells, 
some of great beauty and delicacy. A fine series will 
be found in the Taylor collection. 
The family Mytitin#, or Mussels, is an important 
one, and is known to us chiefly by the genus JAZytzZus, 
enormous quantities of which are used for food or bait. 
The Horse-Mussels (Modio/a) are very large; one 
fine species will be noticed, which is a native of 
California. Unlike the true Mussels, the MHorse- 
Mussels have a habit of burrowing; JLzthodomus 
lithophagus makes its abode in the solid stone, and. 
it is by a species of Lzthodomus that the pillars of the 
Temple of Serapis are bored. The family Arcapa 
contains some fine very solid-looking shells. Z7igonta 
_lamarcki, an Australian species, will attract attention 
in consequence of the beautiful pearly lining to its 
shells. ‘The valves of the family Unionip are also 
remarkable for their lustrous interiors ; the Chinese avail 
themselves of the power possessed by these animals of 
thickening the interior of the shell by the deposit of 
coatings of nacre, and introduce foreign substances 
into the shells of the genus //y7za, which soon become 
covered with the pearly material; some little images 
of Buddha will be noticed in one of the shells thus 
coated. A beautiful series of Unios and Anodons will 
be found in the Taylor collection. 
Tridacna gigas, the Giant Clam, found in the Indian 
Ocean, is a well-known ornamental shell, and exceeds 
all others in magnitude; the single valve under the case, 
although not quite perfect, measures thirty-six inches 
in length, and weighs 76 lbs. Our common Cockle is 
an illustration of the next family, Carpiap&%. ‘There 
are several varieties of C. edule, which will be 
seen in the British collection. Some of the tropical 
