SCLEROS'TOMA (from the Gr. seleros, hard, and stoma, the mouth) is the term applied to a well-known genus of the family strongylidce, belonging to the order of round worms or nematoidea (q.v.). One species, the selerostoma syngarons, is of special interest, as being the cause of the disease in poultry known as the gapes (q.v.). Since the article GAPES was published, it has been ascertained that the eutozoon which infests the wind pipe of the diseased birds is not a trematoid (or fluke-like) worm, but a round worm, possessing many very singular properties. Dr. Cobb()Id, to whom we arc mainly indebted for our knowledge of this worm, removed from a chloroformed fowl with the gapes, seven sclerostomata. " Six were united in pairs, the odd worm being a female, from which the mail had in all liklihood been rudely torn during the withdrawal of the forceps" (Entozoa, 1864, p. 80). The females thus extracted had an average length of f of an inch, while the males scarcely k of an inch. In both sexes, the breadth of the body was nearly uniform throughout, being about A of an inch in the female: and only of an inch in the male. The mouth of the female is furnished with six prominent chitinous lips. According to Siebold, after sexual congress, "there is ultimately it Listing continuity of the sexes by means of an actual growing together" —one of the most remarkable facts ever recorded in natural history. Hence the eggs, which are comparatively large, and many of which contain fully formed embyros, can only escape by a breaking-up of the body of the paient. •• By whatever mode," says Dr. Cobbo "the young make their exit from the shell, it is manifest that prior to their expulsion they are sufficiently developed to undertake an active migration. Their next habitation may occur within the bodies of certain insect larvm, or even in small •land mollusks; but I think it more likely that they either enter the substance of vegetable matters, or bury themselves in the soil at a short distance from the surface." Considering that this worm infests the trachea of the domestic fowl, the turkey, the pheasant, and the partridge, as well as of many birds of less importance (as the magpie, the black stork, the Marling, the swift, etc.). it is of the greatest importance to check its devel
opment.. With this view, the worms must not only be removed by the means described in the article GAPES, and more fully in Cobbold's Entozoa, pp. 90, 91, but they must be totally destroyed after their removal. If they be merely killed and thrown on the ground, the mature eggs will probably remain uninjured; and when decomposition sets in, the young embyroi will, sooner'or later, escape from the shell, migrate in the soil or else where, and ultimately find their way—how, we cannot tell—into the air-passages of cer tain birds, in the same manner as their parents did before them.
Dr. Cobhold, whose classification of intestinal worms will doubtless for many years be the standard one, places the dochmius anchylostomom, or anehylostoma dnodenale (see SamoxovuniE), in this genus, with the mune of selerostoma duodenale. This worm, which usually measures about of an inch in length, is especially characterized by an asymmetrical disposition of four horny, conical. oval papillie, of unequal size, forming the so-called teeth. The female is larger than the male in about the ratio of 4 to 3, and is the more numerous in the ratio of 3 to 1. This worm was first discovered by Dubini at Milan in 1838, and though at first thought rare, is now known to be tolerably common throughout northern Italy. It is remarkably abundant in Egypt, where Pruner found it in nearly every corpse, sometimes in hundreds of specimens, in the jejunum, and to a less extent in the oluodenum. Griesinger, in his memoir On the Frequency of Entozoa in Egypt, and the they orcosfon (1854), considers that about one-fourth of the popula tion are constantly suffering from a severe annimic chlorosis, occasioned solely by the presence of this parasite. A tolerably full account of this disorder, and of the treatment to be adopted, is given by Kilehenmeister in his Manual tf Parasites, vol. i. pp. 386— 389.