Fig. 7.— View from ventral aspect of double monster belonging 

 to Class III., i.e. with union in pectoral region, the adjacent pectoral 

 fins not being represented. Horizontal sections in PI. XV. figs. 52, 

 53, XVI. figs, sr, ^;. Diagrams of vertebral column, heart, etc., in 

 PI. XVII. fig. 63, XIX. fig. 75, XX. fig. 84. Description under 

 Class III. on pp. 18-19. The body wall over the yolk is ruptured 

 along the middle line. ( ■ 3. ) 



Fig. 10. — Double monster with union in posterior part of body. 

 Tli.- union is obliquely by the ventral aspect of each twill, and the 

 tail has three angles. See pp. 21-22. Compare PI. VI. fiss. 27 20. 

 and I'!. VII. fig. 31. (x 3 .) 



Fig. 8. — View from above of double monster, with unioi 

 pectoral region, the adjacent pectoral fins not being represented. 

 For references see under Fig. 7. ( :■: 3, ) 



I'll,. 11. — Double monster with union by posterior part of body. 

 The tail is irregular, but resembles that of the preceding specimen. 

 One of the twin heads is smaller than the other, and shows the 

 condition of cyclopia. See pp. 7, 40 and PI. XXIV. figs. 100-104, 

 also PI. XXV figs. 107, 108. 1 j 1 



^ — ^tf^F^V 



FlG. 9. — View from the side of a double monster, with union 

 behind the pectoral region. One of the twins is much reduced in 

 size. The posterior part of the body is single and symmetrical. 

 For description see under Class V. on pp. 20-21. ( x 3.) 



Fig. 12.— Double monster with symmetrical ventral union of the 

 posterior parts of the twin bodies. Two pairs of pelvic fins are 

 present, each pair being made up of components derived from 

 different twins. The tail has four angles as in the section shown in 

 PI. VII. fig. 30. Description under Class VI. {/>) on pp. 22-23. 

 (X3-) 



PL. II. 



