MUSEUM OF COMPARATIVE ZOOLOGY. SD 
PLATE XV. 
Brain, upper view, $ nat., and transverse sections. 1, olfactory lobe; 
3, oculo-motorius ; 4, trochlearis ; 5, trigeminus; 7 and 8, facialis and acusticus ; 
10, vagus. 
PLATE XVI. 
Brain: A from beneath, B from the side, and C in longitudinal section. Num- 
bers as in Plate XV.; 2, optic nerve; 6, abducens; 9, glosso-pharyngeus. 
PLATE XVII. 
Lower view of heart, $ nat. 1, auricle; 2, ventricle; 3, bulbus ; 4, sinus; 
.5, dark tissue between cardiac and abdominal chambers. 
PLATE XVIIL 
B. Heart in longitudinal section, showing cavity in ventricle, 6, and valves in 
bulbus, 7. 3 nat. 
C. Parasite, Zetrarhynchus wardii, } nat. Figs. 8 and 10 from the sides, 
and Fig. 9 from the front. 
PLATE XIX. 
1. Ovaries and oviducts, $ nat. 0, ovary; ov, oviduct; zg, nidamental gland. 
2. Longitudinal section through cloaca and oviduct, nat. size; showing ov, ovi- 
ducts; ct, intestine; wa, urethral aperture; c/, cloaca; ab-p, abdominal pore ; 
p, cecal pouch. Reversed in transfer. 
3. Section of intestine showing spiral valves. 
PLATE XX. 
A. Transverse section of abdomen showing the tropeic folds, 3 nat. 
B. Same section, natural size. 
C. Longitudinal section of nidamental gland, ? natural size. 
