ep. 
pr. 
PLATE IV. 
Fie. 1 — Exterior of shell, dorsal view. 
. Anterior portion. lig. Ligament. 
. Posterior portion. l. v. Left valve. 
. Dorsal portion. r. v. Right valve. 
Fic. 2— Young shell before leaving the gills. 
. Valves. by. Byssus. 
. Hinge-line. c. Cilia. 
. The animal. s. Serrated spines. 
Fie. 8 — Epidermis. 
. Pigment cells. 
Fic. 4— Prismatic layer, transverse section. 
Fie. 5 — Narceous layer, transverse section. 
Fie. 6 — Section of the shell. 
Epidermis. nac, Nacreous layer. 
Prismatic layer. 
Fic. 7 — Enlargement of secreting tubes of the liver. 
Fic. 8-— Parasite frequently found on the animal. 
Fic. 9 — Enlargement of tentacles of the branchial siphon. 
Fie. 10 — Enlargement of muscular fibres. 
Fre. 11-— Mass-of-the tubules of-the-lver. 
Frer-i2 > Young Anodonta. 
