6 CLARKE ON A DOUBLE-HEADED VERTEBRATE. 



Figs. 5, 6. Figures from life. Enlarged twelve diameters. 



Fig. 5. Dorsal view of the double monster, m, mouth of right or larger head ; m', mouth of left or 

 smaller head ; e5, left eye of larger head ; ca, right eye of larger head ; cc^ outline of cranial cavity as exter- 

 nally indicated ; 5r, branchiae of right side of larger head; those of the left side of larger head are not 

 marked, to avoid confusing the figure ; al, anterior limb of right side ; ea', right eye of left or smaller head ; 

 hr a', branchiae of right side of smaller head ; br V, branchiae of left side of smaller head ; aV, anterior limb 

 of left side; so, median line and indication of spinal column. It is worthy of notice that there seems to be 

 externally no connection between the smaller head and the spine, cf, caudal fin. 



Fig. 6. Ventral view of the same, eb', left eye of left or smaller head; pi, posterior limb; cl, cloaca. 

 The figure is not completed posteriorly, as the structure of these parts is fully shown in fig. 5. Other letters 

 as in fig. 5. 



