FIG. 97. Transverse section through the 

 triple monster illustrated in the three pre- 

 ceding figures. The section passes across the 

 middle of the body in the principal embryo, 

 while the two defective embryos are cut 

 obliquely through the pectoral region, and 

 through the hinder part of the brain. All 

 three alimentary canals are here separate, 

 those of A and B being cut in the region of 

 the oesophagus, and having beside them the 

 pneumatic ducts. In A and B also a well- 

 developed head-kidney is seen, but in the 

 principal embryo the section passes some 

 distance behind this organ. Other references 

 are given under Fig. 94. ( x 10.) 



Fir;. 98. Transverse section belonging 

 to the same series as the last figure, but a 

 little further back. The body of embryo 

 A is taken up chiefly with the nerve tissue 

 of the medulla and spinal cord, while B 

 shows a section of the tiny fourth ventricle 

 and medulla. Below the' bodies of .-/ and 

 B are seen the Wolffian ducts, air-sacs, 

 stomachs, and the hepatic tissue belong- 

 ing to these embryos. A pelvic fin of the 

 principal embryo comes into the section 

 on its left side. Other references are given 

 under Fig. 94. ( x 14.) 



Fi<;. 99. Transverse section from same 

 series as the last two figures, but a con- 

 siderable distance further back. The 

 bodies of the two defective embryos are 

 now uniting, and they are seen to be 

 made up of very irregular tissues, the 

 spinal cords being hardly recognisable. 

 The intestinal canals of these embryos 

 are joining together, the part seen towards 

 the middle being the commencement of 

 the common terminal portion. References 

 under fig. 94. ( x 17.) 



PI.. XXIII. 



