69 



which are consequently all of one sex. The male Filaria medine it- 

 sis is described apparently as a matter of course by nearly all who 

 have written on the subject. I have, however, myself never seen any 

 other form of the worm than that in which young are contained, al- 

 though I have more than once extracted two, or even three indivi- 

 duals from the same limb of the same person. Mr. Owen (Cyclopedia 

 of Anatomy and Physiology, vol. ii. p. 122) remarks that the caudal 

 extremity of the male is obtuse, and emits a single spiculum, and 

 even gives {I. c.) a figure of such an individual ; but with the greatest 

 deference to so high an authority, I cannot help thinking that the 

 appearance presented by the caudal extremity in that instance must 

 have been deceptive, and that it is to be referred to some unusual at- 

 tenuation of the acuminated point in a worm of the usual kind. Of 

 course this is merely thrown out as a surmise, and it would be highly 

 interesting, in fact of the utmost importance, as regards the true na- 

 ture of the worm, to determine the question one way or the other. 

 The principal view, which it is the object of this paper to exhibit, 

 depends for its support entirely upon the non-existence of a male 

 Filaria medinensis in the parasitic condition. But in venturing to 

 make these observations upon the statement of so eminent an observer, 

 I am glad to find myself supported by what Rudolphi says on the 

 same point. He states (Mantissa Entozoologiae, p. 20, 1819) "that 

 in two specimens he had observed the caudal apex, subulate, inflexed, 

 and a line in length ; and in a third, semiterete, rather acute, subin- 

 curvated, but not subulate nor as much curved as in the others;" and 

 he goes on to say " that being struck by the variety of the caudal ex- 

 tremity (which he had taken for a mark of sexual distinction, and 

 had the more readily fallen into this erroneous notion on account of 

 the presence of young ones in the female specimens) he had referred 

 to the distinction of the sexes in giving the specific definition of the 

 Filaria, but had ascertained by renewed examination after the sy- 

 nopsis was printed, that all the above specimens were female and 

 proligerous." 



I have not been able to perceive any anal or other orifice at the 

 caudal extremity of the worm, nor in any part of its length, and con- 

 sequently believe that none such exists. 



The outer integument is white, semitransparent, firm, and of con- 

 siderable thickness, highly elastic and extensible, and marked exter- 

 nally with transverse rugse, as mentioned above. Whether these 

 rugae are dependent upon the presence of distinct circular fibres or 

 not, I have not been able to satisfy myself completely. At first sight 



