T. B. R088ETER ON HYMENOLEPIS FARCIMINALIS. 299 



" Goeze compare ses derniers articles a des boudins ou saucissons 

 (Farchnen)," loc. cit., No. 90, p. 599. 



The more one studies the Cestoidae, more especially those tape- 

 worms which make birds, whether terrestrial or aquatic, their 

 final hosts — which are the most numerous in species (Krabbe, in 

 his day, enumerated nearly 200, and they have been added to 

 considerably by recent discoveries — more especially by Dr. von 

 Linstowof Gottingen) — the more one feels convinced of the futility 

 of diagnosing a species, as the older helminthologists did, solely 

 by the external appearances of the strobila or the formation of 

 the individual proglottides, especially when it is known to be an 

 armed species, and the hooks of the scolex are absent by caducity. 

 I am not advocating a hard-and-fast rule, nor wishing to ignore 

 external characteristics which a careful observer would note as a 

 means of indicating to what species his worm belonged ; but the 

 strobila in the intestine is so liable to undergo such abnormal 

 changes, more especially the terminative uterine portion of the 

 strobila, as to make it difficult, without the cephalic hooks on the 

 one hand and a knowledge of the internal anatomy on the other, 

 to determine the species of the specimen in question. This is 

 forcibly illustrated in Dr. von Linstow's diagrams of his new 

 species (Taenia hyperborea) from Cards lagopus. I am led to the 

 conclusion that it is the absence of any knowledge, either on the 

 part of Krabbe or of the authors quoted by him, of this farci- 

 formation of the terminative segments of this worm that has 

 been the cause of these writers specifically determining their 

 specimens as Goeze's Taenia farciminalis ; and although in. some 

 instances their specimens had uterine segments with the six- 

 hooked brood, still, as I shall show farther on in describing and 

 discussing the genitalia of this worm, there is a great difference 

 in the form of the early uterine as compared with the older 

 terminative segments. 



I took my specimens from the jay (Gawulus ylandarius) and 

 the starling (Stumus vulgaris). Of the former species one 

 specimen in seven possessed them, and they were gregarious in 

 the intestine. They varied in size, my longest specimen being 

 77 — 79 mm. long, and the mature or hermaphroditic segments 



