Davaineid Cestode from a Wallahy. 603 



solution for about a quarter of an hour, after which they were 

 washed for a few hours in runiiiii<5 water, and were tlicn 

 phiced in 70 "/^ alcoliol to which a few drops of iodine 

 solution were added. The a(l(litu)ii of iodine was continued 

 until the colour was permanent, after which it was |)oured 

 off and replaced by 70 °/q alcohol, in which the aninuUs were 

 permanently preserved. The rest of the worms were placed 

 in tap-water, and allowed to remain in it until they were 

 completely relaxed and dead. They were then dropi)ed into 

 a preserving fluid, consisting of equal parts of pure glycerine, 

 70 °/„ alcohol, and distilled water, and as this fluid became 

 turbid it was replaced by fresh preservative. This jjre- 

 servative tends to keep the worms soft, and such specimens, 

 after the excess of glycerine has been washed out by distilled 

 water, are found to stain very well with Ehrlieh's acid 

 haematoxylin. 



(b) Study. — Serial transverse and horizontal sections, 

 7 fx, thick, were cut of mature and ripe proglottids ; these 

 were stained with Ehrlieh's acid haematoxylin M'ith eosin as 

 a counter stain. For the preparation of whole mounts, 

 weak Ehrlich^s acid hsematoxylin was used, and the worms 

 were allowed to stain overnight ; they were then differ- 

 entiated in acid alcohol and eventually i)lued in tap-water ; 

 after slightly pressing them between two microscopic slides 

 and dehydrating them in this condition, the worms were 

 finally mounted in Canada balsam. Acetic alum hasmatin 

 and acetic acid carmine were also tried, but these stains did 

 not give satisfactory results. 



External Characteks. 



(a) External Appearance. — The specimens vary in length 

 from 24 cms. to 35 cms. Anteriorly the body is very niucii 

 attenuated, but posteriorly it gradually increases uiitil about 

 halfway down its length; here the maximum breadth — 

 about 4 mm. — is attained; more posteriorly the strobila 

 again becomes narrowed, so that at its hind end it is only 

 about 1 mm. broad. 



The anterior segments are very narrow, but they become 

 slightly longer posteriorly, and in the middle of the body 

 they are about one-tenth as long as they are broad. Towards 

 the end of the body the segments decrease in breadth and 

 increase in length, so that the terminal segments are about 

 twice as long as they are broad, and somewliat barrel-shaped. 

 The posterior lateral margin of each segment projects 

 slightly over the segment following: this is more marked 



3U* 



