PORTEK: TRICHONYMPHA. 57 



The questious of reproduction and development in Trichonympha, 

 though interesting, are very difficult, and I shall not be able to say 

 much on them. 



I have chanced upon three individuals, which 1 at first thought to be 

 stages of division (Plate 3, Figs. 24-2G), but having seen only these 

 three, and these being all from the same host, I am now inclined to 

 think that they are simply abnormal forms. But whether these are 

 normal or abnormal, I believe that division must be of rare occurrence. 



Leidy has figured several forms (Plate 51, Figs. 11-20), always found 

 associated with Trichonympha, which he thinks may be their young; 

 but 1 believe that not all the forms referred by Leidy to Trichonympha 

 can be the young of that genus. Perhaps, indeed, none of them are. 

 Those which seem to me to present the best evidence of being the young 

 of Trichonympha are shown in Plate 3, Figs. 27-29 (compare also Leidy's 

 Plate 51, Fig. 11). These individuals possess a nucleus situated in about 

 the same relative position as that of the adult Trichonympha, and are 

 provided with long cilia. The cilia begin at the base of a smooth knob 

 (Fig. 29), with which the anterior end of the animal terminates, and 

 follow from there the course of deep spiral gi'ooves that have the direc- 

 tion of the threads of a right-hand screw, not, as one might infer from 

 Leidy's Figure 11, that of a left-hand screw. The grooves are much 

 closer together on the anterior than on the posterior portion of the para- 

 site, and consequently, as in the adult Trichonympha, the cilia are much 

 concentrated into this region. Again, as in the adult Trichonympha, a 

 bunch of long cilia trails out behind the parasites of this type. More- 

 over, the anterior cilia alone are used, as in the adult Trichonympha, for 

 locomotion, the body often remaining daring locomotion perfectly rigid 

 and the posterior cilia quiet. 



This spring (1896) I have noticed a great many specimens of this 

 parasite with a very much enlarged, apparently swollen, anterior knob 

 (Fig. 28) ; but what this condition signifies I have been unable to 

 determine. 



Notvvitlistanding these several points of agreement, there seem to me 

 to be almost insuperable obstacles to assuming that there is a genetic 

 relation between the two forms. Chief among these is the pronounced 

 dexiotropic course of the spiral groove and accompanying bands of cilia 

 in the supposed young ; whereas in the adult Trichonympha the bands 

 are longitudinal and are limited to the anterior or bell-shaped part. A 

 direct conversion of one of these conditions into the other seems to me 

 highly improbable, while the obliteration of one and a substitution of 



