CHyETOGNATHA. 357 



I in 'ties and other aquatic predatory insects eat with the flesh of the EphemeriA 

 larvrr the encysted young forms, which then develop in the body cavity of 

 their new and larger host to young (im-Jii/In'. Gonlhut uqt/atii-iix J>uj. 



F.-iin. Anguillulidae. * Free living Nematodes of small size. Caudal 

 glands arc sometimes present. The lateral canals are often replaced by the 

 M>-i-allrd ventral glands. 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. Tyli'iiclius Bast. Buccal cavity small, and con- 

 taining a small spine. The female genital opening lies far back. T. scHiulrns 

 Schn.*=trifici 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 011 tu the growing wheat plant. Hei-e 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 coii- 

 tents of the wheat grains. T. dijtxitci'K.u\m. in heads of thistles CCardius) 

 T. Dni-<nni'i Bast, on roots of moss and grass. Hrtcrodera Xrlim-htil Schmidt., 

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

 Duj., divided by Schneider into Lrjitndrru Duj. and PelotJera Schn. Hit. 

 ffc-rilix Duj., head very sharply pointed, mouth with two lips, in the salivary 

 glands of Liinu.r clnrreux. JiJt. angioxtnma Duj. Kh. aj)j>e//t/ in/la fit Schn., 

 in damp earth, 3 mm. long. The larva, which is without a mouth, and has two 

 caudal bands, is found in Arion /'inpiricorviii. Anguillula aeeti = glutinis 

 0. Fr. Miill.. known as the vinegar worm and pasteworm, 1 to 2 mrn. long. 



Of the many marine Aiiguillvlid(B (Enoplidoe), we must mention Uori/- 

 luhinix iiHi.i'iiini* Butschli, D. stii<i/t<ilix Duj., found in mud everywhere in 

 Europe. Enclielidiiini inn rim/m Ehrbg.. Enoj>liix tridentatus Duj. 



The abberant families DrxiiinxeoliTiilu- and Clicetosomidte are allied to the 

 Nematoda. 



THE CH.ETOGNATHA. 



The G/uetognatha, f containing only the genus Xagitta, are allied 

 to the Nematodes. They are elongated round worms, with a pecu- 

 liarly armed mouth and laterally placed horizontal tins, the mem- 

 branous edges of which are supported by rays. . The anterior 

 portion of the body is sharply separated ofT as a head, and bears in 



* Davaine. " Eecherches sur rAnguillule du ble nielle," Paris. 1857. Kiihn, 

 l - Ueber das Vorkommen von Auguilluleu in erkrankten Bllithenkopfen von 

 Dipsacus fullonum.'' Zritsrhr.fiir irixx ZnoL. Tom IX.. 1859. Bastian, '-Mono- 

 Graph of the Anguillulidfe or free Xematoids. marine, land, and fresh water.'' 

 London, 1864. U. Biitschli. " Beitrligc 7.ur Kentniss der freilebenden Xema- 

 tuden." -V<"-. Acfn, Turn XXXVI.. 1873. Lad. Ocrley, " Muiiugraphie der 

 Aii-uillulidcn/' Buda-Pest.. 18SO. 



j Compare A. Krohn. " Anatomisch-physiologisclie Beobachtungen iiber die 

 Saintta bipnnctata." Hamburg. 1844. It. Wilms. " De Sagitta mare germani- 

 cum circ.'i insulam Helgoland incolente.'' Beroliui. 1846. Kowalevski, " Em- ' 

 bryologische Studien an Wiirmern und Arthropodeii." Man. dc TAi-uii. 

 St. Pt'tcrxhii/ii'ij. Turn XVI. 0. Hertwig, - Die Chsetognatha. eine Mono- 

 " 



graphie." Jena. isso. 



