PLATE XXXIV 



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A.— AMPHIOXUS, EXTERNAL SURFACE LEFT SIDE : THE MOUTH SURROUNDED 

 BY THE ORAL CIRRI IS OX THE LEFT. B.— AMPHIOXUS DISSECTED, SHOWING 

 PERFORATED PHARYNX, AND BEHIND THIS THE STRAIGHT INTESTINE. 

 ABOVE THE INTESTINE IS THE NOTOCHORD, AND ABOVE THIS THE NERVE- 

 CORD. C— LARVA OF AMPHIOXUS ENLARGED, LYING ON LEFT SIDE, ON 

 WHICH IS THE LARGE MOUTH: THE GILL OPENINGS TO THE RIGHT OF 

 THE VENTRAL EDGE, BETWEEN THE TWO ATRIAL FOLDS. D.— A SOLITARY 

 ASCIDIAN (ASCIDIA MENTULA), LEFT SIDE EXTERNAL SURFACE. E. THE 

 SAME. INTERNAL STRUCTURE SHOWING PHARYNX INTESTINE, HEART AND 

 BLOOD-VESSEL (IN BLACK) 



