840 MR JAMES MURRAY ON 



correspond to the four limb-bearing segments, the head and fourth legs being drawn in 

 out of sight. There is a constriction in the centre of the body, and the anterior and 

 posterior portions are very similar in form, but the posterior end is broader. There 

 are deep constrictions towards each end, and the posterior one becomes important 

 afterwards. 



On the ventral side are six little conical stumps, the remnants of three pairs of legs 

 (fig. 3). When the cyst has just been formed there are claws on those little stumpy 

 legs, but after a short time it is found that they have been withdrawn through small 

 openings at the ends of the legs (shown in fig. 3). I was never so fortunate as to 

 witness the withdrawing of the claws. 



The shagreening of the general surface continues on to the legs, but becomes more 

 obscure towards the ends of the stumps, and the part surrounding the pores through 

 which the claws are withdrawn is a clear membrane. 



From the moment when it attains its final form, the skin of the cyst is brittle and 

 so dark and opaque that its contents can only be dimly seen, and it is impossible 

 to study the further developments within it. To do this it is necessary to break open 

 the cysts. 



When a cyst is broken open immediately after its completion, we find within it the 

 animal much as it was before encystment, only smaller, and possessing all its organs, 

 teeth, pharynx, claws, etc. 



When a cyst is broken open at a somewhat later period, say after it has been formed 

 for two or three days, the contained animal is found to have contracted and taken an 

 elliptical form. The shagreened skin remains as an outer case, within which the 

 elliptical body lies loosely. 



The elliptical cyst (fig. 4) is covered by smooth, yellow, transparent skin, without 

 trace of external limbs, but still containing a complete animal, having legs, claws, teeth, 

 and pharynx. 



The origin of this inner covering is puzzling. The outer case, which appears to be 

 secreted from the skin, retains traces of the form of the animal. The inner case appears 

 to be of quite a different nature, and looks like a true skin, having no dots or evidence 

 of having been secreted, and no trace of segmentation or limbs. Yet, if not secreted, 

 how account for the complete animal within it ; and, if secreted, how account for its 

 regular egg-like form ? 



The most remarkable part of the process follows. Cases broken open about a week 

 after their completion are found to enclose the elliptical yellow cysts as before, but these 

 no longer contain complete animals. 



If the contents of a cyst can be squeezed out without rupture, there appears an 

 almost amorphous mass, without trace of limbs, claws, teeth, or pharynx. It is un- 

 fortunate that the opacity of the outer case prevents the study of this remarkable 

 change in its various stages. 



Professor Richters has now under observation some cysts of species which have not 



