PLATE IX. 

 LATE EMBRYO OF CHIMERA COLLIEI. 



a. cl. Antero-pelvic clasper. mix. Mixipterygium. 



a. d. f. Anterior dental plate. p. d. p. Palatine dental plate. 



/. o. Frontal organ. 



Fig. 50. Late embryo, age about six months, corresponding approximately to Balfour's stage p 



in shark. Lateral view. The attachment of small masses of yolk to the side of the 



embryo is probably artifact. The opercular fold has here been partly cut away, so as to 



expose the gills. X about 3. 



Fig. 50 a. Ventral aspect. External gills removed from the left side. 

 Fig. 50 b. Dorsal aspect. 

 Fig. 50 c. Anterior aspect. External gills removed from the left side. Observe particularly the 



large size of the frontal clasping organ. 

 Fig. 50 d. Ventral region, showing extent to which the opercular fold has overgrown the gill 



lamellae. A detail is given as to the origin of the external filaments. 

 Fig. 50 e. Region of the mouth. This shows especially the appearance of the sensory canals and 



the early condition of the dental eminences and of the labial cartilages. 

 Fig. 50 f. Ventral fin, showing the early condition of the mixipterygium and of the antero-ventral 



clasping organ. 

 Fig. 5 g. External gill filaments, giving detail of vein and artery. 



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