The Whip-Worm. 327 



antelopes, and deer ; in the goat, the giraffe, and also, according 

 to Diesing, in the porcupine (Histrix cristata). 



If attention be directed to the accompanying plate illustra- 

 tion, it will be seen that we have represented two individuals of 

 T. affinis, the upper one being a female, and the lower a male, 

 which is easily recognized by its gracefully curved spiral tail. 

 To the naked eye these whip-worms do not differ materially 

 from those found in our own bodies, but on microscopic ex- 

 amination a distinction, especially in the males, is readily ob- 

 served. With the pocket-lens, as we have elsewhere remarked, 

 the surface of the worm appears smooth throughout; but, 

 when highly magnified, peculiar markings are seen on the an- 

 terior thin portion, which probably also extend over the body 

 proper. The so-called neck presents a tolerably uniform 

 thickness along its entire course ; it is so narrow as to measure 

 only from the -p-g-g- to T 4-gf of an inch transversely, whilst the 

 finely-pointed head itself, immediately below the mouth, has a 

 diameter less than the yoVtt °f an inch. In the fresh state the 

 head appears to be lobed; or, rather, furnished with two 

 alasform lobed appendages, as represented in fig. 2 ; but in 

 preserved specimens these appearances either partially or 

 entirely disappear, leaving one in doubt as to their true nature. 

 Kuchenmeister has noticed the evanescence of apparently 

 similar structures surrounding the mouth of Trichocephalus 

 disjpar, and therefore supposes that the lobes in question are 

 due to the presence of a peculiar organ, capable of eversion 

 and inversion, and not merely the result of accidental sarcode 

 globules. Be that as it may, it is surprising to notice how 

 completely other well-marked external and internal characters 

 alter or disappear from shrinking and distortion caused by 

 immersion in spirit. This observation especially applies to a 

 very peculiar longitudinal band which commences a little 

 below the head and can be traced on one side of the neck the 

 whole way down to the beginning of the so-called body. This 

 band, which is remarkably distinct in fresh specimens, was 

 first discovered by Dujardin, who states it to consist of pro- 

 minent and pointed papillse. Wedl has also described it as 

 consisting of little warts and spines; whilst Kuchenmeister 

 goes so far as to compare these little prominences to the hook- 

 lets present on the intromittent organ of the male. 



According, however, to our own observations, this band is 

 made up of projecting, bluntly-pointed, polygonal, epidermal 

 cells, which in certain adjustments of the focus refract transmitted 

 light so strongly, that the band of them looks as if it consisted 

 of a regularly arranged series of pigment spots, as shown in fig. 

 3 a; at other times the centre of each cell becomes clear (a), and 

 the irregularly polygonal character of each individual cell is 



