E ii(l<>i><i rasitcM. 519 



in tlie middle of tlie coiled aiiinial, sueli as that described and 

 tipjured by J. Johnstone from the gurnard (1905, p. 297). On 

 reference to the work of Cobbold, Leidy und others, especially 

 that of Prof. Linton (U.S.A.), it is evident that these encysted 

 nematodes are very closely allied to, if not the same species as, 

 those found " encysted and encapsuled " in the peritoneum in 

 such tish as herring, mackerel, cod, salmon and shad, in the 

 Northern Hemisphere. The cuticular covering described above 

 is the embryonic cuticle in which these worms are still enclosed, 

 the enclosed worm being apparently an immature Ascaris, the 

 jaws, etc.. of wiiicli are iiisutticicntly developed to allow of exact 

 specific determination. The varying stages of development 

 found in the mass at my disposal resemble closely those found 

 by Linton in different tishes, in (loc. cit., 1901), pi. x., fig. 115 ; 

 pi. xi., figs. 121, 127; pi. xii., figs. 132, U.3 ; pi. xiii., figs. 148, 

 102. 16:3 : pi. xiv.. figs. 168, 179. 181, the most characteristic 

 reseml)ling figs. 143, 162, 163, 168, 179 and 181, from a nvim])e;- 

 of different fishes. I have found, also, that the same individual 

 will give a difl:'eient appearance of developmental stage of the 

 anterior end according to the clearing reagent used. Those 

 drawn by myself were cleared in carbolised absolute. As it is 

 unlikely that the young of different species would be so closely 

 and similarly intertwined with each other, it seems highly prob- 

 al)le that some at least of Linton's " Ascaris spp. immature '' 

 will be found to be different stages of the same species. 



Now as to the name to be applied to these forms. In the 

 British Museum Catalogue of Entozoa (1853) are records and 

 synonyms by Dr. Baird of 2 Nematodes found in the peritoneum 

 of fish — viz. : — 



F I Jar id (?) marina (jDage 7). 



= (lording niarinwi, Linnaeus, etc. 



=: (iiirdnm Jiart^ngiiin, Bloch. 



^ A-^raris marina. Cuielin. 



r= Axrarix Jialeris. Gmelin. 



= Curiillanux haferis, Fabricius. 



= ('(ip<ii/aria liahris. Zeder. 



= Fusaria marina, Zeder. 



= Filaria marina. Rathke. 



= Filaria capsnlaria. Riidolphi, etc. 



