NEMATODA 209 



centre (Leuckart). The tail of the male shows a simple, 

 thick, cup- shaped bursa, which is destitute of rays, and 

 partly conceals the simple spiculum. The tail of the female 

 is blunt and pierced by the centrally placed anal opening. 

 The vulva is situated near the head in the ventral line. The 

 eggs are stout and oval, measuring ~ f in length by about 3 i s // 

 in breadth. 



As regards development the recent researches of Schneider 

 have shown that certain kinds of fish play the part of inter- 

 mediary bearer. Balbiani preserved the ova in water for more 

 than a year without their hatching, and all his attempts to rear 

 the larvae in the intestines of the dog by direct experiment 

 failed. Similar feeding experiments upon fishes and reptiles 

 also failed. The embryo, when removed from the egg, measures 

 yjj" in length. It is vermiform, having a pointed head and 

 simple mouth. Balbiani describes the buccal cavity as con- 

 taining a protractile stylet. Notwithstanding the negative 

 results obtained by Balbiani's experiments on fishes, Schneider 

 (from anatomical data, which Leuckart confirms) has placed it 

 almost beyond question that the worm hitherto known as 

 Filaria cystica is the sexually- immature Eustrongylus gigas. 

 This worm is found encysted beneath the peritoneal membrane 

 in Galaxias scriba and Synbranchus laticaudatus. It is worthy 

 of remark that the genus Galaxias comes nearer to the Sal- 

 monidas than to the pike family, whilst the Synbranchi are 

 tropical oceanic fishes. Probably the sexually-immature worm 

 occurs in other fishes, especially the Salmonidae. 



Eemarkably fine examples of the adult worm may be seen 

 in the Hunterian Collection, Lincoln's Inn, and in the Museum 

 of the Royal Veterinary College. The human example is 

 undoubtedly genuine. The dissections in the Hunterian Col- 

 lection of specimens were made by me in 1865. Objection has 

 been taken to my description of the oesophagus as "spiral." 

 In Sheldon's specimen it is certainly twisted upon itself, precisely 

 in the manner in which Davaine has also figured it (' Traite/ fig. 

 68) ; but I cannot here give further anatomical particulars. 

 Drelincourt found two worms sexually united in the kidney. 

 When once the parasites have gained access to this organ, 

 rapid destruction of the glandular substance follows. Ulti- 

 mately the kidney is reduced to the condition of a mere cyst or 

 bag, which, besides the worms, contains a quantity of sanguineo^ 

 purulent matter. Frequently only one worm is prese 



