ECONOMY OF THE ACEPHALOCYSTS OF AUTHORS. 



ECHINODEKMATA. 

 ENTOZOA. ANALOGUES. 



IV. Diplozoon IV. Asterias. 



V. Scutella V. Tristoma. 



VI. Distoma hepaticum. Authors. . VI. Echinus. 



CRUSTACEA. 

 VII. Echinorynchus VII. Lernea. 



ANNELIDA. 

 VIII. Ascaris VIII. Lumbricus. 



EXPLANATION OF THE PLATES. 



PLATE XIV. 



Fig. 1. Acephalocystis simplex ; natural size. 



Fig. 2. Portion of the external tubular membrane of Diskostoma acephalocystis, very slightly magnified. 



The part at A was situated near the Hydatid ; the other part at B was on the peritoneum at a 



little distance from the Hydatid, and had not arrived at a full state of growth. 

 Fig. 3. Diskostoma acephalocystis of the natural size. The tubular or external membrane is drawn 



rather boldly for the purpose of shewing its structure. 

 Fig. 4. Small portion of the substance of an artheromatous tumour, very much magnified. It .is stated 



by some authors that Ilydatids, after a certain time, change into such tumours. 

 Fig. 5. Portion of the external tubular membrane of Diskostoma acephalocystis, very much magnified ; 



A A large disks ; B smaller disk on the surface of a larger one ; C tubes running to the edge of 



large disk ; D tubes running to the edge of smaller disk ; E stomata. 

 Fig. 6. Internal surface of a small portion of the Acephalocystis simplex, very much magnified, to shew 



young cells being developed between the two membranes of the vesicle. 

 Fig. 7. Small portion of the external or tubular membrane of Diskostoma acephalocystis, very highly 



magnified. A large disk ; B smaller disks upon its surface ; C tubes running to the edge of large 



disk ; D tubes running to the edge of smaller disks ; E stomata ; F gemmules containing young 



vesicles or cells. 

 Fig. 8. Small portion of a thin transverse section of omentum, very highly magnified, shewing the young 



of Diskostoma acephalocystis before they have got into the abdominal cavity. 

 Fig. 9. Another small portion of the tubular membrane of Diskostoma, shewing the structure of the 



disk. 



PLATE XV. 



Fig. 1. Small portion of the gelatinous substance from Diskostoma, very much magnified, shewing the 

 manner in which the blood globules arrange themselves when effused into that part of the para- 

 site's body. 



Fig. 2. Small portion of abdominal parietes vertical section shewing the young gemmules of Diskos- 

 toma in various stages of growth. A A external membrane ; B peritoneum ; C C gemmules thrown 

 VOL. XV. PART IV. 7 P 



