CEEATODUS, PROTOPTBBUS, AND C'HIM.ERA. 505 



PLATE LXXXIV. 



Fig. 8. Heart of Protojjterus annectens, x 4 linear, seen from the front. CA, arterial 

 cone ; Au, auriclar appendages ; a-, additional lobe of right side of auricle ; 

 Vn, ventricle ; Per, attachment to pericardium. The right appendage of the 

 auricle is thrown back so as to expose the constricted neck of the conns. 



Fig. 9. The same heart, back view. Si, sinus venosus ; vc, vc', apertures of veins enter- 

 ing the sinus ; other letters as in fig. 8. 



Fig. 10. The same heart, back view, with sinus and auricle opened by a median slit. 

 AW, auriculo- ventricular curtain valve; 2^6', basal fibro-cartilage ; 6'ay, incom- 

 plete sinu-auricular valves ; other letters as in fig. 9. 



Fig. 1 1 . Heart of Protopterus opened from the front by a median vertical cut as indi- 

 cated by the dotted line in fig. 8. CA, arterial cone ; Au, auricle ; Vn, ven- 

 tricle ; FC, basal fibro-cartilage ; v v, rudimentary pocket valves ; Sp v, spiral 

 valve ; ul v, second long valve of the upper limb of the conus. 



Fig. 12. View of the lower border of the arterial cone, showing the pocket valves 

 (greatly enlarged). 



Fig. 13. Heart of Chimcera monstrosa, front view. CA, arterial cone; Vn, ventricle; 

 Au, auricle. 



Fig. 14. The same heart with the anterior half of the conus and ventricle entirely 

 removed. CA, conus arteriosus; B, limit of arterial cone corresponding to 

 the lower limit of the upper vertical limb of the Dipnoous arterial cone ; 

 AW, auriculo-ventricular valve ; A, fleshy pad ; Au, auricle ; Vn, ventricle. 



Fig. 15. The same heart seen from behind, with the auricle opened. Sa v, sinu-auricular 

 valve ; Si, sinus venosus ; other letters as in fig. 14. 



VOL. X. — PART XI. No. 4. — February \st, 1879. 3 z 



