273] NORTH AMERICAN MONOSTOMES 55 



to 112/i wide, margin irregular. Shell gland ovoid, anterior to and a little 

 larger than the ovary. Cirrus pouch tubular, elongate, extending to the 

 beginning of the second body third. Prostate gland and cirrus covered 

 with papillae. Vagina straight, muscular, as long as the cirrus pouch. 

 Vitellaria external to the ceca, extending from the middle of the body 

 caudad to the testes. Excretory bladder forked, opening to the exterior 

 just dorsal to the posterior end. Eggs thick shelled, 20 to 22/i long by ll/>i 

 wide, having two long polar filaments, one at each end. 



Habitat: Duodenum Host: Fiber zihethicus 



Locality: Nebraska Collector: ? 



PARAMONOSTOMUM Liihe 1910 



This genus, created by Liihe to hold Monostomum alveatum (Mehlis) 

 Creplin, is characterized by Liihe as follows: Body compressed, egg shaped, 

 greatest breadth a little caudad from middle of body, posterior end broadly 

 anterior tapering and pointed; anterior half of ventral surface thick set 

 with short heavy spines. Ventral glands absent. Cirrus pouch weakly 

 muscular. Vagina usually one-half length of cirrus pouch. 



Type species: Paramonostomum alveatum (Mehlis) Crepl. 



American representative : Paramonostomum echinum nov. spec. 



Barker (1916) criticises the erection of a new genus on the basis of the 

 absence of the ventral glands on the ground that the number of rows vary 

 from two in N otocotylus diserialis Ssinitzin to five in N otocotylus quinqueser- 

 ialis Barker and Laughlin. Yet the same author accepts the genus Catatro- 

 pis of Odhner founded on the non-protrusible character of these same 

 glands. There is apparently as much reason to accept the genus of Liihe 

 based on their absence as that of Odhner founded on their non-protrusi- 

 bility. 



PARAMONOSTOMUM ECHINUM nov. spec. 



Thin cup-shaped worms, 2 to 2.5 mm in length by 0.6 to 0.7 mm in 

 maximum width which is found at the beginning of the posterior third 

 of the body length. No ventral papillae have been found on these worms, 

 the anterior half of the ventral surface being covered with heavy spines 

 5ju in length. These curve caudad and are thick set according to the 

 definite pattern shown in figures 13 and 16. Mouth terminal, spherical, 

 102 to 125/i in diameter, followed by a short esophagus which bifurcates 

 to form the intestinal crura; these follow an undulating course to the 

 posterior end of the body where they end blindly. Crura provided with 

 short but definite internal and external diverticula. Genital pore situated 

 just posterior to the intestinal bifucation. Cirrus pouch extends from this 

 point into the beginning of the second third of the body. Vagina one-half 

 as long as the cirrus pouch. Prostate gland and cirrus without papillae. 



