90 



Memoirs of the Indian Museum. 



[Vol. I, 



translucent cuticle which plainly shows parallel lines of growth. The inner part of 

 each ridge is composed of two layers of large nucleated cells between which capillary 

 blood vessels are often to be seen. 



F19.2, 



ScaJe 



1mm. 





^ 



c.Tn 



km. 



F, 



t2^,3. 



, ^-''p.^. 



Fig. 2. — Section of the wall of the mid gut, x 60: cm. = circular muscle fibres ; /.w. = longitu- 

 dinal muscle fibres. The cuticular intima is very thick and shows lines of growth. 



Fig. 3. — Section of the wall of the hind gut, x 60. 



Fig. 4. — The gizzard wall : i = the cuticular intima ; 2 = the endotheliun ; 3 -= homogeneous 

 layer or " basement membrane " (the representation of this layer is somewhat exaggerated); 4 = the 

 outer fibrous coat. 



The anterior part of the hind gut is remarkably thin ; so thin, that its coherence 

 must be largely due to the cuticular intima, a slender wavy layer formed upon the 

 endothelium. External to the endothelium are a few muscle fibres; these are 

 much more plentiful posteriorly, where they are arranged longitudinally for the most 

 part. 



The Vascular System. 



Owing to their friable nature in the preserved specimen, it was found impossible 

 to trace the blood vessels to any extent. The large heart and its principal arteries, 

 however, afforded material for a partial description (pi. x, fig. i). The heart is 

 5 cms. in length and i cm. in its greatest breadth. It lies upon, and in close contact 

 with, the hind gut, and occupies the last thoracic and the five abdominal segments. 

 For descriptive purposes it may be divided into anterior and posterior halves. The 

 anterior half, which is roughly oval in transverse section, gives off eleven vessels : one 

 median artery from its anterior end, and five pairs of lateral ones. The posterior 

 half of the heart, from which no vessels are given off, forms in transverse section a 

 quadrilateral figure, somewhat greater in height than in breadth. 



