300 DR. T, S. COBBOLD ON HUMAN ENTOZOA. [NoV. 25, 



unacquainted with the male. It is by no means improbable, how- 

 ever, that one or other of the numerous male examples of Filarice 

 belonging to Mr. Carter's closely allied genus TJrolabes may turn out 

 to be the long sought-for male of Dracunculus. The anatomy of 

 the adult viviparously producing female is well known ; but its mode 

 of gaining access to the body is not absolutely determined, although 

 an ultimate and complete solution of the problem cannot long be de- 

 layed. "With extreme probability we may fairly assume that the 

 young gain access by permeating the sudorific ducts of the skin, and 

 that the maturation of the ova and embryos takes place after they 

 have invaded the host. Females extracted from the human body 

 have been described as attaining a length of 8, 10, or even 16 feet ; 

 but it is worthy of remark that Mr. Carter has never found them 

 more than 32 inches long in the island of Bombay. The grown 

 females resemble elongated sacs distended from end to end with my- 

 riads of young Filarice. The discovery of their viviparous mode of 

 reproduction is, I believe, due to Jacobson ; yet it is only within 

 comparatively recent times that this discovery has become generally 

 recognized. The structure of the young has been ably investigated 

 by Carter, Busk, Robin, Moquin-Tandon, and others ; and I have 

 myself independently worked out their anatomy from specimens of 

 remarkably fine Dracunculi, kindly placed in my hands by the late 

 Sir George Ballingall. I found the young in a beautiful state of pre- 

 servation, although the adult females had been preserved in Prof. 

 Ballingall' s private museum for a period of thirty years. In regard 

 to the structure of the young, most of us agree in recognizing a 

 slightly trilobed or tripapillated mouth ; but Carter fails to recognize 

 these tubercles, regarding the oral aperture as simple or " puncti- 

 form ; " the body throughout its three upper fourths is cylindrical 

 and finely striated transversely, after which it rapidly contracts to 

 form the slender sharply-pointed tail. Robin, Moquin-Tandon, and 

 myself recognize a distinct, rounded anal orifice ; but whilst Prof. 

 Busk has not recognized its existence. Carter, on the other hand, calls 

 that which we described as the anus a gland, placing the alimentary 

 outlet on one side and a little above it. Carter (whose figures, by- 

 the-by, are very diagrammatic) may possibly be right ; but I must 

 further observe that Robin describes the anus as surrounded by a 

 small hood or suspensory contractile lip, whilst he also speaks of 

 a prolongation of the intestine downwards in the form of a cul de 

 sac behind and beyond the anal orifice. The walls of the digestive 

 tube are transparent and homogeneous, and fill up the perivisceral 

 cavity without being organically united to the parietes of the body. 

 Other disputed points in respect of the structure of the young can- 

 not here be particularized ; but in connexion with their peculiar 

 economy both Busk and Robin have noticed the important fact that 

 they will revive after having undergone a considerable amount of 

 desiccation. Into the antecedent history and probable genetic rela- 

 tions of Dracunculus, we do not now propose to enter ; but one inter- 

 esting circumstance seems to me especially worthy of notice. Mr. 

 Carter mentions that in a school of fifty boys bathing in a certain 



