24 



ENTOZOA. 



as tlie process is essentially the same in all the flukes, and he 

 succeeded in tracing the rest of the stages without interruption. 

 Thus the sporocyst, at the time of its first separation from the 

 cUiated embryo, presents a very simple appearance (d), showing a 

 sort of head and body, the latter containing a digestive tube or 

 coecum in its interior. There is also a slight fissuration of the 

 caudal end, indicating the first rudiments of two appendages, 

 which, in a more advanced condition of the sporocyst, look like a 

 pair of imperfectly fashioned limbs. These lobed appendages are 



Fia. 5.— Egg (o), embryos (i, c), and pporocyst (<?), (Distoma militaee, Sudol^U).—Ymi 



Beneden. 



also present in the sporocystic condition of the Monostoma mutabile 

 previously alluded to, as well as in other trematode larvEe. In the 

 next stage here indicated (fig. 6 e) we have a well- developed head 

 (a) and body (b), the tail (c) becoming pointed and strongly pro- 

 nounced. The limb-like lobes (d) project on either side at the 

 lower part of the body, and an oval sucker (e) makes its appear- 

 ance in front. This communicates by a short passage with the 

 oesophageal bulb (/), and passes directly into the single digestive 

 coecum or stomach (g), which contains a variable number of 

 rounded particles, supposed to be the food. At this stage, also, one 

 or more incompletely developed cercarise (i) may be seen in the 



