115 



in first, as one meets with many forms in which the suckers only 

 protrude at the extremity, like four knobs. The suckers then follow 

 and are turned completely in, so that their proper outer surfaces look 

 towards one another, the coronet of hooks lying beneath them. In 

 this state, which has been so often described, the animal has not 

 more thau half its previous length, and takes on a great variety of 

 forms, oval, rounded, heart-shaped, &c. Instances of these varieties 

 are figured in both plates. 



b. The secondanj cysts. — When the fluid contained within one of 

 the large Echinococcus-cysts is emptied into a glass vessel, it is at first 

 turbid with minute white bodies, but these rapidly subside and form a 

 white sediment at the bottom of the vessel. These white bodies vary 

 in size from J^th of an inch in diameter downwards to xg-o*^- They 

 are the secondary cysts. 



Under the microscope these bodies are seen to be delicate sphe- 

 roidal sacs, containing Echinococci. The largest examined (PI. XXIX. 

 fig. 9) had at least thirty of these in its interior. It consisted of a 

 very transparent structureless membrane, apparently lined by a deli- 

 cate granular film, which was most distinct near the pedicles of the 

 contained Echinococci. These Echinococci in fact were not free hke 

 those contained in the primary cyst, which I have previously de- 

 scribed, but each was attached by a delicate cord, more or less resem- 

 bling the " appendage" of the free Echinococcus, to the inner wall of 

 the secondary cyst (PL XXIX. fig. 8), and radiated thence inwards. 

 These Echinococci resembled in all respects those previously described, 

 except that I could observe no cihary motion in them * ; they were in 

 all conditions of protraction or retraction, and exhibited the ordinary 

 movements. None were ever found free in a secondary cyst, and the 

 members of each cyst, as well as those in different cysts, were as 

 nearly as may be of the same size and degree of perfection. 



The space left between them in the interior of the secondary cysts 

 was sometimes filled with a clear fluid, and at others more or less 

 obscured by granules. In none of those observed by me was there 

 any trace of the peculiar mode of development of the contained Echi- 

 nococci from the granular contents of the secondary cysts described 

 by "Von Siebold (vide infra). 



The membrane of these cysts was traversed by a meshwork of fine 

 clear delicate vessels, with distinct walls and about ~^t^ to -J-th 

 of an inch in diameter. These were not folds, as their lumen could be 

 clearly seen at the edge of a cyst (fig. 8). They terminated in a some- 

 what wide space at the base of the pedicle of each contained Echino- 

 coccus, and in one instance I traced a vessel for some distance into 

 this pedicle. There were no cilia nor granules contained in these ves- 

 sels, but they precisely resemble those canals of which traces were 

 seen in the Endocyst, and their development will, I think, show that 

 they are identical with them. 



* This may well arise from my not having examined them till the 28th. 

 Lebert appears to have found the observation of the cilia to be favoured by the 

 interposed membrane of the secondary cyst (vide ir^fra). 



