290 NEMATHELMINTHES. 



Fam. 6. Anguillulidae. * Free-living Nematodes of small size, usually with a 

 double swelling on oesophagus. Caudal glands are sometimes present. The 

 lateral canals are often replaced by the so-called ventral glands ; males with two 

 equal spicules. Some species either live on or are parasitic in plants ; others 

 live in fermenting or decaying matter. The greater number, however, live free 

 in earth or water. Tylenchus Bast. Buccal cavity small, and containing a 

 small spine. The female genital opening lies far back. T. scandens Schn. = 

 tritici Needham, in mildewed wheat grains. When the grains of wheat fall the 

 dried embryos grow in the damp earth, bore through the softened membranes, 

 and make their way on to the growing wheat plant. Here they remain some 

 time, perhaps a whole winter without alteration, until the ears begin to be 

 formed. They then pass into the latter, grow, and become sexually mature, 

 while the ear is ripening. They copulate and deposit their eggs, from which 

 the embryos creep out, and at length constitute the sole contents of the wheat 

 grains (ear-cockles). T. dipsaci Kulm, in heads of thistles (Carduus) ; T. Davainii 

 Bast., on roots of moss and grass. Heterodcra Schachtii Schmidt., roots of the 

 beet-root, also of the cabbage, of wheat, barley, etc. 



Rhabditis Duj. (divided by Schneider into Leptodera Duj. and Pelodcra Schn.), 

 with two strongly-developed oesophageal swellings, of which the hinder has a 

 dental armature. Rh. flexilis Duj., head very sharply pointed, mouth with two 

 lips ; in the salivary glands of Limax cinereus. Eh. angiostoma Duj. 



Rhabditis nigrovenosa, the free dioecious generation of Rhabdonema (Ascaris) 

 nigrovenosum, which is hermaphrodite, and infests the lungs of frogs. 

 Rhabdonema strongyloides Lkt. (Anguillula intestinalis) in intestine of man in 

 Lombardy and Cochin China, causing diarrhoea ; Anguillula stercoralis is the 

 free Rhabditis generation of this.f Rhabdonema (Leptodera) appcndiculata 

 Schn., in damp earth, 3mm. long. The parasitic form, which is without a 

 mouth and has two caudal bands, lives in Arion empiricorum, and does not 

 attain sexual maturity until after its escape from its host. It is dioecious, 

 and gives rise to free-living, also dioecious, Rhabditis forms, many generations 

 of which may succeed one another. 



Bradynema Zur Strasse, Br. regidum v. Sieb. in the body-cavity of the beetle 

 Aphodius fimentarius, without mouth, intestine, anus, excretory and nervous 

 systems. Mainly consisting of uterus full of embryos ; viviparous ; larvae, male 

 and female, set free in body-cavity, bore through into intestine, and pass out by 

 anus of host. According to Zur Strasse the female larvae die without pro- 

 ducing eggs, while the male larvae become protandrous hermaphrodites, and 

 enter in an unknown way the body -cavity of their host. This account requires 

 confirmation. 



Allantonema mirabile Lkt. in the beetle Hylobius pini, 3 mm. long, sausage- 

 shaped, surrounded by a membrane, and attached to tracheae in the body-cavity ; 

 without mouth, intestine, anus; are protandrous hermaphrodites, with a free- 

 living dioecious Rhabditis generation. 



* Davaine, " Recherches sur 1'Anguillule du ble nielle," Paris, 1857. Kiihn, 

 "Ueber das Vorkommen von Anguillulen in erkrankten Bliithenkb'pfen von 

 Dipsacus fullonum," Zeitschr. fur wiss Zool., torn 9., 1859. Bastian, "Mono- 

 graph of the Anguillulidae or free Nematoids, marine, land, and fresh water," 

 London, 1864. 0. Biitschli, " Beitrage zur Kentniss der freilebenden Nema- 

 toden," Nov. Ada, torn. 36, 1873. J. G. de Man, "Diefrei in der reinen Erde 

 und im sussen Wasser lebenden Nematoden der Nied. Fauna," Leiden, 1884. 



t Leuckart, Ber. d. k. Sachs. Gesel. d. Wiss, 1882. 



Z.f. w. Z.,54, 1892, p. 700. 



