22 ILLINOIS BIOLOGICAL MONOGRAPHS [240 



he said is seen with difficulty. A little later in this work in the description 

 of Notocotyle {Monostomum) verrucosunt he employed the term "la ven- 

 tuose anterieure ou plutot le buccal," applying it to the spherical muscular 

 bulb at the extreme anterior of this worm a Notocotylid, evidently mistak- 

 ing this structure for the same structure termed the pharyngeal bulb in 

 the earlier work. His descriptions show clearly that the same organ which 

 in the distomes is termed pharynx is here termed anterior sucker or buccal 

 bulb. 



Some years later Monticelli (1892) described the mouth as small in 

 Monostomum mutabile and Monostomum expansum; of greater or less size 

 in Ogmogaster plicatum and Monostomum galeatum; circular in Monostomum 

 hippocrepis and Monostomum trigonocephalum ; ellipsoidal in Monostomum 

 cymhium and Monostomum ornatum. It is usually ventral and generally 

 situated in the extreme anterior end. When present a prepharynx of 

 variable length is situated directly in front of the pharyngeal sucker, the 

 "anterior sucker or buccal bulb" of Van Beneden. Monticelli thus dis- 

 tinguishes between the funnel shaped tapering canal of von Siebold (1835) 

 and the adjoining posterior structure; and designates it as a prepharynx. 

 He says that in Notocotyle and some other genera of this family the 

 prepharynx is wanting and that then the pharynx is anterior and plays the 

 role of an anterior sucker. For this reason he designates this structure in 

 these genera as a sucker pharynx. 



Braun one year later, refers to the description of Monticelli and sug- 

 gests that a sucking organ has been developed out of the pharynx. In 

 1901 the same author refers to the "bulbus buccalis" of Van Beneden, or 

 pharynx of Monticelli, as a Mundsaugnapf which he says is followed by 

 the esophagus. In another paragraph of the same work when describing 

 Monostomum trigonocephalum Rud. (since removed to the genus Prono- 

 cephalus by Looss) collected from the intestine of the sea turtle he says 

 that the sucker is 0.12 mm long and 0.09 mm broad and again states 

 that it is followed by a straight esophagus 0.3 mm long, without a phar- 

 ynx. Thus Braun has construed the muscular structure at the extreme 

 anterior in the Notocotylidae, Pronocephalidae and other families of this 

 group to be a development of a structure similar to that termed pharynx 

 by Monticelli in the Cyclocoelidae. 



Barker and Laughlin (1911) accept this view without comment and 

 describe the worms Notocotyle quinqueserialis as clinging to the intestine 

 of the muskrat tenaciously with the well developed oral sucker. They 

 found no evidence of a pharynx. 



Taschenberg (1879) describes the mouth in the genus Didymozoon 

 as an opening followed by a funnel shaped duct leading to the pharynx. 

 This he states to be generally characteristic of the entire group. Lonnberg 

 (1891) found in Didymozoon lampridis the well developed sucker (pharynx of 



