].lb NEW GYRODACTYLOID TREMATODES FROM AUSTRALIAN JISHBS, 



avoid unnecessary confusion we have deemed it expedient to rename the species 

 as Monocotyle minima-. 



MONOCOTYLE ROBUSTA, U.Sp. (Tcxt-flg. 1.) 



This is a ratlier small stout species, measuring about .72 mm. in length 

 and .30 mm. in maximum Ijody-breadth. The disc is nearly circular and re- 

 lativelj' very large, measuring about .31 mm. in diameter. The anterior end of 

 the worm is naiTow and dome-shaped, but the body immediately behind the 

 pharynx broadens out, reaching its maximum breadth in the region of the ovary, 

 then narrowing considerably to be joined by a relatively broad pedicle to the 

 disc. 



The disc bears a small sucker in its middle, from whose walls eight radii 

 pass outwards and divide the margin into as many marginal suckers. The disc 

 is therefore a very powerful adhesive organ, but its efficiency is increased by a 

 pair of large hooks situated on the outer angles of the two posterior suckers. In 

 other species minor hooks have been described, one belonging to each sucker; 



Text-fig.l. — jMonocotyle i-obus/a , entire animal. 



but in this form their presence has not been seen with certainty. Each of the 

 larger hooks has two roots, one very, long, the other relatively short and pro- 

 vided with minute muscles. 



The. skin is quite devoid of papillae. Longitudinal and circular muscle- 

 layers can be distinguished, but only the latter is well developed, especially in 



