60 ILLINOIS BIOLOGICAL MONOGRAPHS [278 



period; that the parasites reach the climax of sexual maturity soon after 

 the host emerges from the winter quarters. They discharge their eggs 

 and pass out from the body of the host soon after the time of spawning, 

 and at the close of this period the hosts are relatively free from infection. 



Observations of the writer verify the sexual inactivity of the parasite 

 Heronimus chelydrae during the early part of the winter and the copious 

 discharge of mature miracidia in early spring. On the other hand these 

 turtles did not become free from infection at any time during the period 

 of the experiment. It must be kept in mind however that the turtles used 

 were not subject to natural conditions, i.e., no opportunity was afforded 

 for hibernation and no eggs were deposited during this time. That trema- 

 todes adapted to partially closed cavities can live longer than for a single 

 reproductive phase is evident, since in the instance reported above in which 

 the host has been kept for a period of more than three years, the two para- 

 sites found were sexually mature, and were producing large quantities of 

 ripe eggs when the host was examined; this is true also in one other case 

 in which the host was kept for more than eighteen months. 



COLLYRICLIDAE Ward 1917 



This family was created to hold the genus Collyriclum of Kossack and 

 is circumscribed by Ward as follows: 



"Small to moderate sized monostomes with discoidal compressed, not 

 muscular body, broader than long. Oral sucker weak; pharynx present; 

 ceca simple, long, capacious, not united. Genital pore ventral near center 

 of body. Vitellaria follicular, scanty, antero-lateral; ovary much lobed, 

 symmetrical. Uterus posterior, in irregular coils which show an antero- 

 posterior tendency, terminal region enlarged. Testes oval, symmetrical, 

 behind ovary. Eggs very small. Adults parasitic in dermal cysts on abdo- 

 minal surface of the skin of birds." 



In the light of our present knowledge of these forms the family diagnosis 

 must be modified with respect to the condition of the testes. Tyzzer (1918) 

 has shown the testes of the American species to be irregularly lobed and 

 not oval as described for the European species, Collyriclum faba by both 

 Kossack (1911) and Jegen (1917). The writer has examined a number of 

 specimens of Collyriclum colei Ward and has found the observation of 

 Tyzzer stated above to be correct. 



Type and only genus: Collyriclum Kossack 1911. 



American representative: Collyriclum colei Ward 1917 



COLLYRICLUM COLEI Ward 1917 

 Syn: M onostoma faba Cole 1911 



Collyriclum faba Tyzzer 1918 



Diagnosis: Small hemispherical worms, 4 to 5 mm in length and breadth 

 by 3 mm thick. Cuticula covered with spines 35 /z in length, arranged in 

 groups which form rather regular rows around the worm. Mouth terminal 



