468 
Fig. 
Fig. 
Fig. 
TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
46, 
PLATE IX. 
Dorso-ventral section of small P. opercularis, 
through centre of adductor. x 54. 
Section of small P. opercularis (same plane as 
fig. 46), through digestive gland and anterior 
end of adductor. x 4. 
Section of small LP. opercularis (same plane), 
anterior to adductor muscle through visceral 
mass. X 9. 
Section of wall of auricle, showing the excre- 
tory cells of pericardial gland. Zeiss apo. 1°65. 
Section of digestive gland, showing alveoli with 
pigment, and digestive ducts. x 170. 
Trans. section through renal organ. x 50. 
Part of previous section more highly magnified. 
x 400. 
Section through ovigerous and seminal alveoli 
of gonad (almost ripe). x 200. 
Striped muscle fibres from adductor, in surface 
(b) and edge view (c). Zeiss apo. 15 mm 
