NO. 1780. 



A NEW CESTODE PARASITE— HALL. 



141 



from the anterior edge of the sucker to the tip of the rostellum is 

 370 pt, the entire length of the head being 735 /i and the maximum 

 breadth being 676 ft. In another specimen, mounted in glycerine 

 and viewed en face, the breadth was 534 by 752 /jt. The bulb of the 

 suckers has a diameter of 215 to 265 jx in mounted specimens. The 

 muscular bulb bearing the hooks has a diameter of 307 /x. The 

 hooks are located on the anterior end of the rostellum at some distance 

 from the suckers. In the specimen from the dog, the small hooks, fif- 

 teen in number, are all that are present. A marked hiatus shows where 

 another is missing from the original circlet of sixteen. In examining 

 specimens of the lynx tapeworms, no 

 large hooks were found in the first speci- 

 mens studied. Later, heads were found 

 with an occasional large hook present, 

 though it appears that the attachment of 

 the large hooks is very weak. One perfect 

 specimen had only twenty-eight hooks, 

 making the apparent range of twenty- 

 eight to thirty- two in number of hooks. 



/lomm 



Fig. 3.— Small hooks of dog tapeworm. 



/fomm. 



Fig. 4.— Large and small hooks of 



LYNX tapeworm. 



The small hook has a strongly curved blade, a very short posterior 

 root or handle, and a broad, almost cordiform, anterior root or 

 guard. (See figs. 3 and 4.) The hook length from tip of the blade 

 to the distal end of the posterior root is 93 to 95 /x in the tapeworm 

 from the dog, and 93 to 98 p. in the tapeworm from the lynx. In 

 the large hook as found in the tapeworm from the lynx, the blade 

 is less curved than in the small hook, the anterior root or guard is of 

 almost the same dimensions as in the small hook, but the straight 

 posterior root or handle is longer, so that the total length of the 

 large hook is 145 pi. (See fig. 4.) 



