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KATHLEKN H ADDON. 
parasite is generally called the “anterior portion” or “pro- 
boscis,” presumably because other parasitic copepods, such as 
Lei-neea and Pennella, are attached by what is obviously 
the anterior end, and it is not likely that Herpyllobius 
would depart from the general rule, especially as the males 
are attached anteriorly ; it is also evident that the external 
])ortion must be posterior because of the presence of the egg- 
sacs. Owing, however, to the extreme degeneracy attained 
by this animal, the “ anterior portion” has lost any cliarnc- 
teristic structure it may have had and become jnerely 
absorptive, thus recalling a similar state exhibited by the 
Text-fig. 1. 
t/ 0 
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Rhizocephalan Cirripedes ; for tliis reason I propose to speak 
of this portion of the parasite as tlie “ root system.” 
'I’his was not visible in ray specimens until the worms were 
sectioned. Levinsen (9), however, was able to see it within 
the host by simpl}' removing the elytra of the worm. He 
described it as a thin red streak lying parallel to the worm’s 
gut, and on removing the worm’s skin it appeared as a long, 
narrow, tongue-shaped body lying free beside, or underneath 
the pharynx of its host ; posteriorly it emerged from the 
worm’s head and was continuous through the stalk with the 
external part (Text-fig. 2). The length of the root system of 
the parasite according to this observer was 4 to 5 mm., 
the breadth 1 mm., and the thickness i to i mm. ; the 
broadest part was just behind the middle, and posterior to 
this it tapered, broadening again just before the stalk, where 
