144CS.S.446) THE MONONCHS 



tutes one of the most frequent, as wJl as most reliable, bits of evidence 

 concerning thi food-habits of mononchs. 



Voracity. Mononchs are voracious. Often the remains of several 

 other nemas are to be seen in the intestine of a single one of them. The 

 writer once had under observation a specimen that had swallowed four 

 large rotifers in quick succession, all tail-end first. The file of rotifers 

 could be clearly seen in the intestine of the mononch. Aquatic mononchs 

 are fond of rotifers. The characteristic "gizzards" of the rotifers, being 

 rather indigestible, are often found in the posterior part of the intestine. 



Rectum. From the slightly depressed anus, the lips of which are 

 sometimes rather pronounced, the refractive rectum, usually about as 

 long as the anal body diameter, extends inward and forward, and is sep- 

 arated from the intestine by a distinct constriction. There is no pre- 

 rectum, though the contrary impression is sometimes created by a con- 

 striction caused by a mural commissure (?) some little distance in front 

 of the rectum. 



Feces. From the region of the anus relatively powerful transverse 

 muscles pass obliquely backward to the body wall, and find their proximal 

 attachment in the dorsally submedian regions. These anal muscles are 

 more strongly developed in mononchs than in most nemas. A powerful 

 defecating apparatus is needful to such gluttons, since their feces are 

 sometimes bulky, owing, apparently, to the fact that the contents of the 

 intestines of their victims often prove indigestible. Probably this indi- 

 gestible material is to a considerable extent vegetable in its nature; at 

 any rate, it frequently happens that the feces are bulky, and this fact 

 seems to account for the strong development of the rectum and the anal 

 muscles. 



Caudal Glands; Spinneret 



The Cement. The caudal glands, when present, are always three in 

 number, and are arranged in a cluster or series opposite to or immedi- 

 ately behind the anus. If the tail is short, the foremost gland is usually 

 dorsal while the two submedian glands are arranged 

 side by side; if the tail is long all three may be ar- 

 ranged tandem. Apparently there are always three 

 separate ducts, one from each gland, each having a 

 separate ampulla; these latter are arranged side by 

 X750 ^^^^ side in a group at the spinneret. Often, however, the 

 spinneret is simple in form and presents ducts that 



FIG. 13. Mononch . . J 



tail showm* the three form only indistinct ampullae. Some idea of the man- 

 caudal glands, their , .., 



ducts, the spinneret, ner and rate of secretion of the caudal glands may be 



and its secretion . . 



<*<*.). derived from an examination of the adjacent illustra- 



tion, which shows a spiral mass of the cement substance secreted by them. 

 This spiral mass was coagulated by the fixing fluid in which the specimen 

 met its death. 



