On this view, therefore, at least two asexual generations (embryo and scolex) alternate with a sexual one (proglottides); and in the case of Staphylocystis the cyst contains two asexually produced generations, so that in such forms three stages (embryo, primary scolex-buds, secondary scolices) intervene between the proglottis of a Cestode and that of its offspring.
The cyst is filled with a toxic fluid and may bud off new or daughter scolices.
Single cyst germinating (X200).
Repeated fission (brood-formation) within a cyst has also been observed, as in Pyrocystis and Ceratium; and possibly the chains of Ceratium and other (fig.
The peculiar feature of the larval history of Cestodes is the development in most cases of a cyst or hydatid on the inner wall of which the scolex is formed by invagination.
The cyst should be treated like a liver-abscess, by incision through the abdominal or thoracic wall, by circumferential suturing and by exploration and drainage.
At m the ideal mode of origin is shown in order to illustrate the fact that the daughter cyst is comparable to the fore-body of a cysticercus.
When that occurs, the cyst is dissolved and the minute fluke works its way down the alimentary canal into some part of which it inserts its suckers and commences to feed on the blood of its host.
Pyrocystis (Murray), often encysted, spherical or crescentic, becoming free within cyst wall, and escaping whole or after brood-divisions as a form like Gymnodinium; Gymnodinium (Stein); Hemidinium (Stein); Pouchetia (Schutt) (fig.