CESTODARIA 437 



despite much restaining and section-cutting on my part, and 

 I have therefore omitted descriptions of the finer tissue 

 structures ; I have also omitted to supply the details of struc- 

 ture of such organs as the cirrus and cirrus-sac, the uterus wall, 

 the ovary, testes, and vitellaria, not because it is impossible 

 to do so, but because I do not think that the information thus 

 to be gained is, at least at present, worth supplying,^ in view 

 of the major differences separating these four new species from 

 all species hitherto described. 



Wenyonia virilis, gen. et sp. nov. Woodland, 1923. 



Of this species (PI. 24, figs. 1, 2), the most remarkable in form 

 of the four to be described in this paper and the type species 

 of the new genus, I possess altogether some twenty mature 

 specimens and five small immature specimens. This parasite 

 was found in the Nile Siluroid S y n o d o n t i s s c h a 1 1 , Bloch- 

 Schneider, 1801, common at Khartoum, presumably in the 

 intestine. Two of my specimens are much larger than the 

 remainder, one of the two measuring 52-5 mm. in length with 

 a maximum breadth of 3 mm., and the other (unmeasured and 

 now sectionized) being of about the same dimensions. The 

 other mature specimens range from 11 mm. to 16 mm. in length, 

 with maximum breadths of 1-5 mm. to 1-7 mm. Apart from 

 the difference of size of body and differences in the lengths of 

 the several regions of the body relative to the length of the body 

 as a whole, the two large specimens are identical with the 

 smaller specimens, and I have no reason to believe that the 

 former belong to a distinct species or variety. In shape of 

 body Wenyonia virilis is very constant and characteristic 

 (PI. 24, fig. 1). The Caryophyllaeid body is usually divided into 

 the three regions : (1) the ' Kopf ' or anterior extremity, 

 usually distinguished from the next region by expansion, 

 form, or muscular differentiation, or all three ; (2) the ' Hals ', 



^ In most cases these inquiries would involve considerable additional 

 section-cutting of somewhat brittle material which has been flattened 

 and preserved in balsam for some years. Should this additional informa- 

 tion become necessary in the future, the material is always at hand. 



NO. 267 G g 



