438 



DISEASE OF ONCHOLA1MS 



direction, i.e. caudad, in this species as in the others. Moreover a different 

 explanation of this exceptional case seems more plausible, namely, that in 

 0. appendiculatum the demanian organs are in a deteriorated condition. The 

 fact that this species is the only one that almost invariably presents disease 

 in the posterior extremity of the adult females may harmonize with the 

 supposition that the demanian system of this species is in a deteriorating 

 and perhaps useless condition. The nonconsecutiveness of the posterior 

 cells of the moniliform glands in 0. appendiculatum, and the appearance 

 of crystals on the outer surface of the enteric efferent, (Fig. 3) suggest 

 decadence in this anomalous species. 



In 0. appendiculatum the uvette is reduced to a mere ampulla; and is 

 almost as greatly reduced in nigrocephalatum. In neither of these is it at 

 all likely that the uvette itself could produce any very appreciable secretion 

 flowing into the uterus, and yet in both species the uterine tube is better 

 developed (or at any rate more obvious) than it is, for instance, in pristiurus, 

 where the uvette is strongly developed. 



Uritis. It is interesting that the females of a number of oncholaims 

 shown to possess demanian vessels seem unusually subject to disease. 



Among such oncholaims, allusion is made to the following typical cases: 



An interesting morphological problem is thus disclosed. As the table 

 indicates, one not infrequently finds oncholaims, especially females, with 

 highly peculiar caudal extremities, sometimes without spinneret or anus, 

 sometimes with these organs present but apparently abortive, or at least 

 peculiar in form, abnormalities probably due to specific disease. Ap- 

 parently the disease is sometimes combated by the nemic organization, so that 

 the posterior end of the nema heals over, and in some cases it seems as if a new 

 anus is formed, and possibly even a new spinneret ! Just how this occurs is 

 not yet clear,*but I have seen both deformed anal openings and deformed 

 spinnerets of female oncholaims that appeared to give evidence of having 

 been imperfectly regenerated after some accident, or, more likely, after uritis. 



* Regeneration seems to be uncommon in nemas. 



Additional articles consulted see zur Strassen's bibliographic list, 1896. 



