MUSEUM OF COMPARATIVE ZOOLOGY. 35 



PLATE XV. 



Brain, upper view, -f nat., and transverse sections. 1, olfactory lobe; 

 3, oculo-motorius ; 4, trochlearis ; 5, trigeminus ; 7 and 8, facialis and acusticus ; 

 10, vagus. 



PLATE XVL 



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-pbaryugeus. 



PLATE XVIL 



Lower view of heart, | nat. 1, auricle; 2, ventricle; 3, bulbus ; 4, sinus; 

 5, dark tissue between cardiac and abdominal chambers. 



PLATE XVni 



B. Heart in longitudinal section, showing cavity in ventricle, 6, and valves in 

 bulbus, 7- -§ nat. 



C. Parasite, Tetrarhynchus icardii, f nat. Figs. 8 and 10 from the sides, 

 and Pig. 9 from the front. 



PLATE XLS. 



1. Ovaries and oviducts, \ nat. o, ovary ; ow, oviduct; ng, nidamental gland. 



2. Longitudinal-seetiou through cloaca and oviduct, nat. size ; showing ov, ovi- 

 ducts ; int, intestine ; iia, urethral aperture ; cl, cloaca ; ab-p, abdominal pore ; 

 jD, caecal pouch. Reversed in transfer. 



3. Section of intestine showing spiral valves. 



PLATE XX. 



A. Transverse section of abdomen showing the tropeic folds, | nat. 



B. Same section, natural size. 



C. Longitudinal section of nidamental gland, \ natural size. 



