UNRECOGNIZABLE FORMS 253 



Hab. Gall-bladder of a Fish {Thymius). 

 Genotype : O. [Trichocephalus] gibbosa (Rudolphi, 1819) 

 (= O. neglecta Diesing, 1851). 



Rudolphi, 1819, Entozoorum Synopsis, 639 ; Kr0yer, 1840, 

 Danmark'sFiske, Copenhagen, i, 596 ; Dujardin, 184:5, Hist. nat. 

 des Helminthes, Paris, 41 ; Diesing, 1851, Systema Helminthum, 

 ii, 81,296. 



9. Pontaraonema v. Linstow, 1878. 



This name appears to be due to a confusion between Ponto- 

 nema and Potamonema Leidy, and species of both genera are 

 mentioned under it. 



V. Linstow, 1878, Compendium der Helminthologie, Hanover, 

 349. 



10. Proboscidea (Bruguiere, 1791) Cuvier, 1798. 



According to Stiles & Hassall, the genotype of this genus is 

 indeterminable. In any case it appears to be a composite 

 group, including species not only of Nematoda but also of 

 Acanthocephala . 



11. Protostrongylus Leiper, 1908. 



This name is mentioned by Leiper (1908, Rep. Wellcome 

 Res. Lab., Khartoum, iii, 191) among genera attributed to 

 his subfamily Metastrongylinae. No species is mentioned, 

 and the name appears to be a nomen nudufn. 



12. Rhytis Mayer, 1839, nee Zeder, 1803. 



Under the name of Rhytis paradoxa, Mayer (1839, Analect.f. 

 vergl. Anat., Bonn, ii, 67) described a remarkable object, ten 

 feet or more in length, said to have been passed [per anum ( ?)] 

 by a cow. It is described as unsegmented and having a 

 mouth, an anus and an alimentary canal, but no other organs 

 were made out. Mayer considered it to be a worm closely 

 related to the Nemathelminthi (including the Nematoidea 

 and Acanthocephala of Rudolphi), but placed it in a separate 

 "Order," Rhytelminthi. According to Tschudi, Miescher 

 and Nordmann (1839, Arch. f. Anal., Phys. u. wiss. Med., 

 Berlin, 220), the object described by Mayer was not a parasitic 

 worm at all. 



13. Sclerotrichum Rudolphi, 1819. 



Syn. Mastigodes de Blainville, 1828, nee Zeder, 1800. 



Body elongate, stiff, composed of two portions, of which 

 the anterior is very slender, ending anteriorly in a disc bordered 

 with fifteen recurved spines, in the centre of which is the mouth. 

 The posterior portion of the body is stout and bears a series of 

 moniliform swellings at its more anterior end. 



