444 W. N. F. WOODLAND 



proves that this region cannot be honiologized with a ' caudal ' 

 appendage. 



The definitions of the new genus Wenyonia — a genus 

 named in honour of my friend Dr. C. M. Wenyon — and the 

 species W. virilis will be stated below. 



Wenyonia acuminata, sp. nov. Woodland, 19'23. 



Of this species (PL 24, figs. 16, 17) I possess four whole 

 specimens, fragments of two others, and a number of longitu- 

 dinal and transverse sections. The parasite is from the Nile 

 Siluroid S y n o d o n t i s me m b r a n a c e u s , Is. GeofTr., caught 

 at Khartoum, and was presumably found in the intestine. 

 Thus W . virilis and W . acuminata are found in two 

 closely related species of Synodontis, and it also so happens 

 that these two parasites are also more closely related to each 

 other than to any other species of Caryophyllaeid, as will be 

 evident from the ensuing descriptions. My four whole speci- 

 mens measured 34-5 mm., 33-0 mm., 26-0 mm., and 17-5 mm. 

 respectively, with corresponding maximum breadths of l-o mm., 

 1-3 mm., 1-2 mm., and 1-2 mm. In all the specimens the 

 greater part of the body was almost uniform in breadth and 

 not unlike that of certain Nematoda, while the head end 

 tapered to a fine point (hence the name of the species) and 

 the posterior extremity was ' stumpy ' and bluntly pointed. The 

 maximum breadth of the body occurs, if anywhere, in the 

 testicular region. The head in most of my specimens was not 

 delimited from the rest of the Ijody by any distinct base, 

 though in two of the specimens (PI. 24, fig. 16) a slight circular 

 ridge or dark band appeared to mark a base, but this I am 

 inclined to think was a transitory contraction, since in both 

 <jf the specimens possessing a base the anterior testes and 

 vitellaria both extended well anterior to this. In the other 

 four whole specimens (of heads) and in my longitudinal sections 

 the head is quite continuous in outline with the rest of the 

 body (PI. 24, fig. 17), and I shall consider of course that it ends 

 posteriorly at the point where the anterior testes and vitellaria 

 commence. 



