124 Froccedings of the Royal Society of Victoria. 



Hind-Terminal Canal and Rectum. 



These two, the first of which forms the hind-intestine of other 

 authors, I will consider together. At its union with the mid- 

 terminal canal the lumen becomes narrower, and the radiating 

 and longitudinal muscles more numerous ; they are separated at 

 short distances, and the cell-wall between projects outwards to 

 form little protuberances ; the cells at these places are larger, and 

 possess large granular nuclei. Viewed on the face, from the 

 inner cavity, they appear as little caverns. 



Towards the rectum the lumen widens, and a large cylindrical 

 sac, 5 mm. long (the rectum), is formed, which becomes con- 

 stricted towards the anus. 



In this organ there are six definite longitudinal folds, lined 

 with glandular cells, forming the so-called Rectal glands ; they 

 are transversely divided in places. The cuticle overlying these 

 glands I have found to be fenestrated, the openings averaging 

 •075 mm. in diameter. About mid-way in the rectum there are 

 four large caverns ranged radially round the wall, in which I 

 have noticed, in fasting insects, large crystals adhering to the 

 wall, which I take to be a nitrogenous salt that has crystallized 

 out from material conveyed from the Malpighian tubes. 



Malpighian Tubes. 



These are fine, flexuous tubes about 14 mm. long, which 

 ramify in the body-cavity. At their attached end they open 

 into the dilated extremity of a common efferent canal (ureter) 

 which, at a distance of 5 mm., enters close to the anterior 

 extremity of the hind-terminal canal. As described and 

 figui'ed by Bordas, (I) the ureter at its junction with the canal 

 protrudes for a short distance to form a neck. 



It was at first pointed out by Leydig that there are, in Gryllo- 

 talpa, two kinds of tubes, Yellow and White. The white tubes 

 are very few in number, and are peculiar to Gryllotalpa ; they 

 are usually crammed witli ovoid concretions of uric acid. The 

 yellow tubes are very numerous, and their cells show within 

 them little spherical yellow grains, and occasionally dark brown 

 acicular crystals. 



For description of these and other excretory organs, the 

 valuable work of Cuenot (2) should ])e consulted. 



