NATURE OF THE DRACUNCULUS, OR GUINEAWORM. 133 
esophagus, the diminution in thickness of the glandular layer, and, in figs. 17 and 18, the 
sudden encroachment of the blunt end of the dilated oviduct or uterus distended with young 
upon the peritoneal cavity. 
. Section about two inches from the head, showing the great thickness of the longitudinal 
muscles, of which the two dorsal and two ventral have come so closely in contact as apparently 
to form a single muscle only in each situation ; (5) dilated uterus, occupying nearly the whole 
of the cavity of the body, and compressing the intestine (a) enclosed in its sheath (4). 
. Appearance of transverse sections through nearly the whole extent of the body of a mature 
worm, showing great distention ofthe uterus, whose walls have become adherent to the 
parietes of the body ; the glandular layer lining the body has been obliterated and absorbed 
by the pressure, and the muscles diminished in thickness: (a, b) intestine enclosed within 
its sheath, compressed into a flat band along the thin edge of one of the longitudinal muscles. 
. Transverse section through the worm, about one inch from the tail ; showing the uterus, near 
its termination, not so much distended, and the reappearance of the glandular layer lining the 
peritoneal cavity. (The figures 13-21 are all magnified about 100 diam.) 
. Integument slit open through the right lateral intermuscular space, showing, (a) two ventral 
muscles; (c) ganglionated nervous cord in centre of lateral space; (d) intestinal canal lying 
parallel and in contact with the edge of one of the longitudinal muscles; (¢) median ventral 
vessel; (f) median dorsal vessel. (x 5 diam.) Tam 
Communications of the muscular fasciculi with one another. (x 100 diam.) 
Portion of one of the muscular fasciculi made up of exceedingly slender fibrille. (x 500 diam.) 
Portion of the parietes slit open through the left longitudinal dorsal muscle: (a) two ventral 
muscles; (5) two dorsal muscles; (c) ganglionated nervous cord; (e,e) median, dorsal, and 
ventral vessels ; (f) tessellated arrangement of glands on surface of muscles, each including a 
nucleated gland-cell; (g) one of similar gland-cells situated in a pulpy stratum over lateral 
space; (4) appearance of gland-cells when much altered from some cause, as noticed in some 
specimens. 
A nerve-ganglion and adjacent portion of nervous cord, highly magnified, with appearance of 
the lateral vessel as seen through it: (a) irregular crenated margin of the ganglion; (2) lateral 
vessel. (x about 600 diam.) 
Mosaic-like collection of glands with longitudinal vessel, scraped from the surface of the two 
dorsal muscles: (a, a) included spherical, light, granular, nucleated gland-cells ; (4) median 
vessel. 
Portion of median dorsal vessel, highly magnified, showing its sinuous course and irregular 
calibre. 
Prats XXII. 
Fig. 20 
Fig. 21 
Fig. 22 
Fig. 23. 
Fig. 24, 
Fig. 25. 
Fig. 26. 
Fig. 27. 
Fig. 28. 
Fig. 29. Glandular projections on the surface of one of the muscles near the head, as seen by reflected 
light: (a, a) large processes near the lateral borders of the muscles; (5, b) very small processes 
over contiguous median borders; (c) median vessel running through this pulpy matter. 
( x about 100 diam.) 
Fig. 30. Three of the projections as they appear by transmitted light: (a) enclosed spherical gland-cell ; 
(b) dot or nucleus, 
Fig. 31. Anterior part of worm (twice the natural size) slit open through mid-dorsal region : (a) cesopha- 
geal sheath; (4) unction of cesophagus with intestine; (c) anterior ovarian tube; (d) anterior 
portion of uterus. 2 
VOL. XXIV. 
