Mr. H. J. Carter on Dracunculua. 31 



sheath divided by a constriction opposite their point of union. 

 (Esophagus (a) straight, narrow, about 1 -600th of an inch in 

 diameter, commencing at the oral orifice and extending back- 

 wards for about two inches, where it becomes slightly dilated, 

 and then joins the intestine; surrounded by the common or 

 peritoueal sheath, within which again is the muscular one, 

 both together forming a cylinder about l-76th of an inch in 

 diameter. Intestine (b b) much wider than the oesophagus, uni- 

 form in calibre, pursuing within its peritoneal sheath a tortuous 

 course throughout the peritoneal cavity from being more or 

 less twisted round the ovisac, and terminating almost close to 

 the tail, in the rectum (c). Rectum only l-8th of an inch long, 

 without sheath, passing into the ventral muscular band or the 

 inner curvature of the tail, beyond which I have not been able 

 to trace it ; that is to say, I have been unable to detect its con- 

 nexion with an anal orifice in the integument over its termina- 

 tion, even under very favourable circumstances for examination, 

 so that if there be any aperture of this kind at all, it must be 

 extremely minute. Peritoneal sheath of the intestine the same 

 or less in width than that of the oesophagus, which thus occa- 

 sionally makes the intestine look less in diameter than the oeso- 

 phagus, commencing from the constriction opposite the union 

 of the oesophagus and intestine, and continued throughout of 

 uniform diameter to the rectum. Hepatic organ consisting of a 

 layer of brownish oil-globules which occupies the interval be- 

 tween the intestine and its sheath throughout, or probably ter- 

 minating a little short of the end of the intestine, as shown in 

 the young Dracunculus (fig. 6 /), where that which is not easily 

 seen in this respect in the adult is supplied at once. 



Organs of Generation (fig. 2). These consist of a large single 

 ovisac (b, b), terminated by an ovary or small ovarian tube ateach 

 extremity. The ovisac uniformly cylindrical throughout, about 

 l-24th of an inch in diameter, and occupying the greater part 

 of the peritoneal cavity, extending to within an inch and a half 

 of each extremity ; membranous, without trace of constriction 

 or projection in any part of its course, and terminating abruptly 

 at each end in a narrow blind tube (the ovary), about an inch 

 long, which is slightly dilated at its extremity. It is the abrupt 

 termination of the ovisac a little short of the ends of the Guinea- 

 worm which makes these parts of the latter more transparent 

 than the rest of the body. The ovisac is filled with young 

 Guinea-worms (all of which are of the same size) and some gra- 

 nular matter. An ovisac 26 inches long and l-24th of an inch in 

 diameter, which is about the average size in the adult Guinea- 

 worm, should, if filled with young of the size to be hereafter 

 mentioned, which is generally the case, contain upwards of half 



