120 Proceedings of the Royal Society of Victoria. 



turn into the cseca, and deflect upward for a short distance 

 (Fig. 3). Six enter one caecum and the remaining six the 

 other. 



The coarse food material is allowed to pass directly through 

 the centre of the gizzard, but is prevented by four chitinous 

 membraneous curtains (which hang down as far as the com- 

 mencement of the fore-terminal canal), from gaining entrance 

 to the ceecal organs, so that its delicate walls, which are 

 unguarded by any chitin, are not injured. 



Hepatic Caeca. 



The hepatic cseca (mid-intestine) are two paired, oblong, and 

 slightly concave organs, measuring 6 mm. through their long 

 axis, and are situated one on each side of the gizzard, and in 

 part attached to its wall (Figs. \a and 3). The anterior of each 

 terminates in a blunt point, a little more forward than the 

 commencement of the gizzard and their posterior end stretches 

 about 2 mm. behind the extremity of the gizzard. The wall 

 lying next to the gizzard is concave, and this wall in each unites 

 with the reflected hinder extremity of the gizzard, and the two 

 caeca entirely surround it. Tlie opposite lateral wall, that is the 

 one of greater curvature, of each, extends posteriorly and joins 

 the anterior extremity of the terminal intestine and entirely 

 surrounds it ; the remainder of the otherwise unattached walls 

 of each, incurve, and unite with each other in the mid-axis, 

 dorsally and ventrally. 



In the lateral wall nearest the gizzard, the cellular layer forms 

 two or more deep longitudinal folds, which project for some dis- 

 tance inwards, and enclose tracheae. The internal surface area 

 is consequently very considerably increased. 



The histological structure is similar in each cfecum. There is 

 no chitinous intima. The wall is spai'ingly supplied with 

 radiating and transverse muscles, and next to these on the inner 

 side is a thin layer of connective tissue, upon' which are situated 

 the cell elements. At close intervals, about -1 mm., the connec- 

 tive layer projects slightly inwards, and between these projections 

 are little chambers or nests, each with a rounded base. These 

 are filled with cells which are supported in a fine reticulum, very 

 apparent in a section cut across the cell nests (see Figs. 7 and 8). 



