87 
The / 7 ’/‘.sT‘ staxje studied wus that of the hexaeanth embryo, as found 
encysted 24-, 88. or 50 hours after ingestion (tigs. 48-4!b 52. 58). gen- 
erally oval, or at times tiask shaped — that is. with a body and a tail. 
Then" may l)e evident at this time a rather ample primary cavity 
which in a llask-shaped embryo is in relation with tli<‘ posterior part 
-ros. 
I 
i 
■ac. 
5f 
55 
58 
Figs. .52, .55.— Hexaeanth embryos of II. mtnu, without cavity, eoiitaining calcareous ctu'puscles. 
Enlarged, (.\fter Grass! ct Rovelli. lS92a. pi. 5, figs. ]0. 11. respectively.) 
Fig. ,54.— Embryo of R. vana after the appearance of ihe primordia of rostellnm ami suckers; 
O'*., suckers: p;-. cor., primary cavity: ms., rostellnm. Enlarged. (After Gra.«si A Kovelli. 1892a, 
pi. 3, fig. 12.) 
Fig. . 5 . 5 . — Longitudinal section of embryo of R. ruum: jir. car.. ])rimary cavity. Enlarsred. (.\fter 
Gras.si & Rovelli. l<S92a. jd. 3. fig. 14.) 
Fig. .5(1. — Longitudinal and slightly oblique section of embryo of R. mum after tlie appearance of pri- 
mordia of rostellum and suckers: ac.. sucker: ro.<.. rostellnm; p/-. car., primary (-avity. Enlarged. 
(After Grass! A Rovelli, 1892a. pi. 3, fig. 15.) 
Fig. 57. — Embryo of R. nann. Same stage as preceding figure, in cross-section; ac.. sucker; ro.--.. ros- 
tellum. Enlarged. (After Gra.ssi A Rovelli, 1892a. pi. 3. hg. 16. ) 
Fig. .58.— Cercocystis of R. mum completely developed. Enlarged. (After Grass! A Rovelli, 1,892a, 
pi. :l, fig. 13.) . 
of the body, and sometimes Avith the tail also (tigs. 5(t. 51). The 
embiwonal hooks are generally found on the tail, sometimes also on 
the posterior part of the body, arranged in pairs. The embryos often 
show irregularities in form, prominences, etc. (tigs. 17-19, 53). In 
the middle of the bodylhere may be found one, two, or three calcare- 
