Fig. 
Fig. 
TRANSACTIONS LIVERPOOL B:OLOGICAL SOCIETY. 
* 
w ww Ww WwW 
iN 
oe) 
dl. 
PLATE VY. 
Diagram of vessels of ctenidium. 
Arteries of lips and labial palps. Nat. size. 
Part of venous system of P. maaimus, from 
injections. 
Ventricle and anterior aorta. 
Trans. section (diagram.) of ctenidium through 
prin. filaments, showing course of blood. x 4. 
Section of ctenidium, transverse to filaments, at 
level of top of ascending filaments. x 180. 
Prats VI. 
Section of ctenidium trans. to filaments, near 
free margin, showing both demibranchs with 
interlamellar junctions. x 110. 
Trans. section of principal and four ordinary 
filaments, near base, showing respiratory 
expansion. x 480. 
Section of respiratory expansion of prin. 
filament in same plane as ctenidium. x 10. 
Respir. expansion of a principal filament. x 20. 
General view of nervous system (P. maaimus). 
Cerebro-pleural and pedal ganglia. 
Visceral ganglia (P. maaimus), showing 
ospbradial ganglia and chief nerve trunks. 
Priats VII. 
Longitudinal section of eye (P. maximus). 
x 150. 
Retinophorae, with rods and ganglionic cell 
layers (semi-diagram.). 
Cells of outer ganglionic layer. Zeiss apo. 1°5, 
with comp. oc. 4. 
