127 
In this case are also found the TeUinidoe, the Teredinidoe 
(shipworms, piddocks, etc). 
Case 10.— continued ; with examples of injury 
they do submerged wood; Pholadidce (burrowing shells); Myidce ; 
SolenidcE (razor- shells). 
Case 11. — PsammobiidcB ; Donacidcs (wedge-shells); Ven- 
eridcE, a very large family, which contains many beautiful shells. 
Case 12. — Venerzdc?, continued; Chamidce, 
Case 13. — Cardidce (cockle-shells) ; Tridacnidcs (giant 
clams). Two very large examples of this family may be seen in 
Hall 25. 
Case 14. — Unionidce (river-mussels). These mollusks live 
in the ponds and streams of all regions of the world, except the 
x:oldest. They abound in individuals and species in our own 
region. 
Case \^.— UnionidcEy continued; Arcidce (ark-shells). 
Case 16 is on the south side of the court at the west end. 
MytilidcB (mussels). Aviculidce (wing-shells). This family 
includes, among other species, the “pearl oysters,” of which speci- 
mens are here shown. Other examples, some beautifully etched, 
may be seen in Hall 32. Among the remarkable genera are 
Malleus and Vulsella, 
Case n .—Aviculidce, continued ; PectinidcE (scallop-shells); 
SpondylidcE (thorny oysters). The last two families contain many 
shells which are interesting on account of their forms and their 
brilliant colors. 
\S.—Spondylidce, continued; Ostreidce {oysters); Den- 
taliidcE (tooth-shells); Chitonidce, The latter is a remarkable 
family and contains over 300 species. The most striking charac- 
teristic of these animals is the serial arrangement of eight pieces 
of shell along the back. 
Case \^.—Patellidoe (limpet-shells) ; Fissurellidce (key-hole 
limpets) ; Haliotidce (ear-shells). 
Case ^10.— TrochidcE und TurbinidcE (top-shells). 
Q>^%^ 2 t\.—Neritidce; Naticidce ; Xenophoridce. 
Csi^e 22, ~ Calyptrceidce (limpets); Ampularidce (apple- 
snails) ; Littorinidce (periwinkles). 
