PLATE VI. 



Fig. LXXV. Transverse section of spider's egg through primitive cumulus (CX 



Fig. LXXV. Cumulus of same section highly magnified. 



Fig. LXXYI. Longitudinal section of spider embryo showing solid mesoblastic 

 somites. 



Fig. LXXVII. Yolk cells (YC) of advanced embryo apparently undergoing 

 endogenous division. 



Fig. LXXVIIP. Longitudinal section of advanced spider embryo with append- 

 ages and hollow mesoblastic somites. 



Fig. LXXIX. Longitudinal section of more advanced embryo. First two 

 abdominal appendages (A & B) are less distinct, and are being folded into form 

 lung book. 



Fig. LXXIX'. Abdominal portion of same figure magnified. 



Fig. LXXX. Longitudinal section of advanced spider embryo showing amni- 

 otic folds (AM) of brain. 



Fig. LXXX'. Cephalic portion of same section highly magnified. 



Fig. LXXXI. Longitudinal section of same embryo nearer median line. 



Fig. LXXXI'. Cephalic portion of the same highly magnified. 



Fig. LXXXII. Highly magnified longitudinal section of brain near median 

 line, 



