CESTODARIA 455 



most one-third of that of the testes and usually much less.^ 

 Parasitic in the intestines of Malacopt erygii and 

 Ostariophysi (Cyprinidae, Mormyridae, and 

 Siluridae ^). 



Archigetes, Leuckart, 1878. 



The sexual apertures are situated within the last quarter 

 of the body-length; and the ovary is near the posterior 

 extremity. The longitudinal extent of the uterus is at 

 most one-third of that of the testes and usually much less. 

 The body of the mature parasite possesses a ' caudal ' 

 appendage posteriorly. Parasitic in the body-cavity of 

 aquatic Oligochaetes. 



Wenyonia, Woodland, 1923. 



The sexual apertures are situated in the anterior half of 

 the body. The longitudinal extent of the uterus is at 

 least equal to that of the testes. Parasitic in the intestine 

 of Siluridae. 



The species known up to the present contained in these three 

 genera are as follows : 



C. laticeps, Pallas, 1781. 



Length of body 11-30 mm. ; breadth of body 0-5-2 mm. 

 Body posterior to the head oval in transverse section. 

 Hind end bluntly pointed or rounded. Head region 



^ With the single exception of Linton's ' Monobothrium hexa- 

 cotyle'(C. hexacotyle), which has eggs measuring only 38-40 microns 

 in length, all species of Caryophyllaeus, as enumerated further in 

 the text, possess eggs about 60 microns in length, or, as in the huge 

 C. armeniacus,80 microns in length. On the other hand, in all three 

 species of Wenyonia the eggs average from 32 to 40 microns in length. 

 These differences are remarkable (especially in view of the body-sizes of 

 the parasites) and may possess a classificatory value. Another difference 

 which may distinguish these two genera is that in Wenyonia the 

 longitudinal muscles are solely contained in a peripheral subcuticular 

 zone, whereas in Caryophyllaeus the longitudinal muscles are disposed 

 in two zones — a subcuticular and an epi-medullary. 



2 I include this family because of the immature species of Caryo- 

 phyllaeus found by me in Auchenoglanis Occident alls and 

 described briefly at the end of this paper. 



H h 2 



