Von Linstow (1872A, pp. 535-537) afterwards found a worm 

 in the goosander (M-erganser merganser [Mergus merganser^ 

 which he identified with Krabbe-s species. Lonnberg (1889, pp. 

 il-10, fig. 1) found a worm in Tadorna vulpanser which he de- 

 .scribed as a new variety: T. gracilis forma Tadornae. The 

 hooks on this worm were much larger than those of the type 

 specimen, a variation which Lonnberg explains as due to host 

 influence. Lonnberg (1890, pp. 10, 30) also records this form for 

 Mergus serrator (= Merganser serrator). 



Von Linstow (1872A, pp. 535-537) found a cysticercoid meas- 

 uring 0.14 by 0.09nim in intestine of a perch (Perca flu\-iatilis). 

 which he looked upon as the young of Taenia gracilis. The 

 larva has also been found in certain fresh-water crustaceans 

 which probably represent the regular intermediate host. Thus 

 Scott (1891, p. 314) noticed an object in a mounted slide of Can- 

 donarostrata Brady & Norman, from the Edinburg district; 

 Blanchard (1891A, pp. 303-332) examined Scott's preparation 

 from Candona rostrata, and after a careful comparison of the 

 hooks of the cysticercoid concluded that this larva belonged 

 in the life cycle of Taenia gracilis. He exiplains von Linstow's 

 finding this same larva in a perch by the fact that the fish 

 had eaten some ostracodes. He introduces the formula — ^the 

 length^a — c, the base=a — b, in measuring the hooks, using it 

 as follows: For T. gracilis ah: ac=30-75. Mrazek (1891, p. 128) 

 cites the Iar\'a for Cypris compressa Baird and Cyclops viridis 

 Fisch. while Moniez (1891, p. 26) mentions it from Cypria oph- 

 thalmica from China. 



The larva referred (o is in all j)robabllity the trne 

 larva of this species, but no infections have as vet been 

 made. 



1. Rostellum with 10 hooks 



13. DREPANIDOTAENIA A.N'ATINA (Krabbe. IStP) Rallllet. 1893. 



(18«!t, Taenia analiiui Krabbe.) 



[PI. IX, figs. 100-111; PI. X, figs. 112-115.] 



Diagnosis: Strobila attains 209nini to SOOmm in length and 



:;nim to 3mm in breadth; worm of TOmm in length has about 



