132 H. CHARLTON BASTIAN ON THE STRUCTURE AND 
as perhaps having also some slight bearing upon this question*. Thus, at Bombay the 
disease is most prevalent during the rainy months of June, July, August, and September ; 
whilst, according to the missionary Duboist, its annual epidemic recurrence in the 
Carnatic villages is in December, January, and February, “ during which time more than 
half the inhabitants suffer ;” and during the same months, as before stated, the disease 
was found to be most frequent by Dr. Chisholm in Grenada and the small Grenadine 
group of the West Indian Islands. 
1 must now bring this long communication to a close, hoping that the subject may be 
taken up by skilful and patient investigators in the countries where this parasite is 
endemic, by whom alone can the missing links in the chain of its history be supplied. 
EXPLANATION OF THE PLATES. 
PLATE X XI. 
Fig. 1. Average-sized Bombay Guineaworm, measuring 30 inches in length by jth of an inch in breadth, 
Fig. 2. Head of Guineaworm, magnified about 100 diameters: (a) orbicular mouth surrounded by aslight 
prominent lip; (4) one of large papilla ; (c) one small lateral papilla; (d) lateral intermus- 
cular space; (e) dorsal intermuscular space; (f) quadrangular or nearly circular opaque space 
corresponding to sheath of cesophagus. 
Fig. 3. Anterior extremity seen in profile: (a) upper and lower papille; (6) one of dorsal muscles; 
(c) lateral intermuscular space; (d) one of ventral muscles. 
Figs. 4, 5, 6, 7. Different forms of caudal extremity : letters as in fig. 3. 
Fig. 8. Irregular transverse markings of the external portion of integument. 
Fig. 9. Set of superimposed lamellae with longitudinal markings: (a) the lines of superficial lamella ; 
(b) lines of lamellz, seen beneath. 
Fig. 10. Two sets of superimposed lamellae with lines in opposite directions: letters as before. 
Fig. 11. A portion of a single glass-like lamella, with its linear markings and jagged torn edges. 
(The figures 8-11 are magnified about 600 diameters.) 
Fig. 12. Three portions of lamella of unequal length, showing that the markings of the under layers cor- 
respond with some portion of the intervals between the lines of the layer above. 
Fig. 13. Transverse section of the worm just behind the head: (a) section of small thick-walled ceso- 
phagus; (4) quadrangular csophageal sheath; (c) granular matter within sheath, with 
esophagus ; (d, d, d, d) four strong mesenteric processes; (e) thin origin of one of the four 
longitudinal muscles; (f) one of the glandular processes; (g) integument. 
Figs. 14, 15, 16, 17, 18. Transverse sections at gradually increasing distances from head up to 1} inch, 
showing the speedy disappearance of mesenteric processes, the disposition of the four longi- 
tudinal muscles and their fasciculi, the varying dimensions of the peritoneal sheath of the 
* This difference would appear to depend more upon variations in the breeding-season of the parent aquatic worms 
than upon differences in the times of incubation or latency of the worm as a parasite. 
T Edin. Med. & Surg. Journ. vol. ii., 1806. 
