182 'P. B. IJOSSETER ON A NEW CVSTICERCUS FF^OM CYCLOPS AdlLTS. 



this conclusion from my previous investigations on other 

 Cysticercoids, and because no other species of natatory birds 

 frequent this piece of water. 



Description of Plate. 



Fig. 1. — Cysticercus of Taenia microsoma. a, cuticle ; h, 

 epithelium of cyst ; c, fluid cavity ; d, in ves ting- 

 membrane of embryonic scolex ; e, embryonic 

 scolex ; /, parenchyma ; g, caudal appendage, x 

 400. 



„ 2. — Evaginated embryo from perivisceral cavity of 

 Cyclops agilis. a, rostrum with hooks ; 6, scolex 

 with suckers ; c, neck. X 400. 



„ 3. — Hook from rostrum. X 600. 



„ 4. — a, 5, c, d as in Fig. 1 ; e, crateriform depression ; /, 

 hooks ; gr, ring-collar aperture ; li, caudal appen- 

 dage. X 400. 



,, 5. — Hook of Toenia fr agilis, after Krabbe. X 920. 



„ 6.— Hook of Cysticercus . . . (?) (Rosseter). x 600. 



