396 
F. 8. BILLINGS. 
Gerlach, Furstenberg, Zenker and Kuchenmeister in Germany. 
Trichina spiralis, is an “extremely minute nematode helminth, 
the male in its fully developed and sexually mature condition 
measuring only 1-18 of an inch, whilst the perfectly developed 
female reaches a length of about 1-8 ; body rounded and filli- 
forin, usually slightly bent on itself, rather thicker behind than in 
front, especially in the males; head narrow, finely pointed, 
unarmed, with a simple central minute oval aperture ; posterior 
extremity of the male furnished with a bilobed caudal appendage, 
the cloacal or anal aperture being situated between these diver¬ 
gent appendages ; penis consisting of a single spicule, cleft above 
so as to assume a Y shaped outline ; female stouter than the 
male, bluntly rounded posteriorly, with genital outlet placed for¬ 
wards—at about the end of the first-fifth of the long diameter of 
the body. Eggs measuring httt of an inch from pole to pole; mode 
of reproduction viviparous.”— Cobbold Entozoa, p. 335. 
*Tlie shell-less ova develop into minute embryos immediately 
on fructification, and completely fill the uterus of the female and 
are born in immense numbers. Scarcely have they become free 
from maternal protection before they begin their migration over 
the autositic organism by penetrating the parieties of the intes¬ 
tines in order to settle themselves in the flesh of the same, as 
muscle-trichinae.” Here, under the protection of a gradually calci 
fying structureless capsule, the migrated embryos, or muscle- 
trichinae, retain their vitality for years, while the sexually matured 
or intestinal trichinae perish, as a rule, in the course of about five 
weeks. The embryos, which sometimes pass away from the auto¬ 
site, or host, with the faeces, may, under favorable conditions, 
give occasion to the development of muscle-trichinae in a second 
autosite by gaining access to its intestinal tract.” 
As we have said, these parasitic pests assume two forms, i. e., 
they may be met with as intestinal and muscular trichinae, the 
first representing the sexually matured, the latter the embryonal 
quiescent, or encapsuled stage of their existence. 
(To be continued .) 
* Leuckart Die Menscliilichen Paraniten, Vol. II, p. 512. 
