JOURNAL OF MICROSCOPICAL SCIENCE. 



EXPLANATION OF PLATE XI, 



Illustrating Professor Van Beneden's paper on Researches 

 on the Structure of the Gregarinae. 



Fig. 1. — Shows the anterior portion of the body of an adult Gregarina, seen 

 on tlie surface, and showing the transverse striations, the 

 different tunics or layers, and the anterior chamber, with the par- 

 tition of separation between the two chambers. (Obj. 9 a im- 

 mersion with ocular 3 of Hartnack.) 



Fig. 2. — Anterior part of the body of another individual as it presents itself 

 in optical section. (Obj. 8 oc. 3 of Hartnack.) Remark 

 that the optical sections of the fibrils on a level with the parti- 

 tion of separation between the two chambers are very nume- 

 rous. 



Fig. 3. — Same part of the body of another individual remarkable for a 

 greater development of the anterior chamber, a greater thick- 

 ness in the partition, and a different arrangement of tlia 

 transverse fibrils near the partition. The longitudinal striation 

 is also to be seen appearing on the surface of the medullary 

 column ; it depends on a particular state of contraction of the 

 cortical layer. The transversal fibrils have been represented 

 in optical sections. (Obj. 10 a immersion and oc. 1 of Hart- 

 nack.) 



Fig. 4. — Optical section of the body, to show the different layers and the 

 distinct character of the granules of each of them. Under the 

 cuticle is seen the muscular tunic composed of a fundamental 

 homogeneous transparent substance and of transverse fibrils seen 

 in this plate in optical section. (Obj. 10 a immersion and ocular 

 3 of Hartnack.) 



Fig. 5. — Three isolated transverse fibrils. It is seen that they are com- 

 posed of refracting corpuscles quite close to one another. 

 (Obj. 10 a immersion of Hartnack.) 



Fig. G. — Part of the body near the nucleus. The body having been torn, the 

 medullary column has partly run ofi", and a cylindroid cavity has 

 been developed between the nucleus and the receding medullary 

 column. The cortical substance remains in its place. 



Fig. 7. — Posterior part of the body of a Gregarina which had rolled itself 

 into a ball surrounded with a cyst of connective tissue in the 

 coats of the rectum. It had still kept its form and all its 

 characters of structure. 



Figs. 8 and 9. — These figures show highly magnified the part of the body 

 of a young Gregarina near the nucleus ; figure 8 shows the 

 optical section, 9 the surface of the body. 



Fig. 10. — Monerian condition of the Gregarina. 



Figs. 12 and 13.— The nucleus appears ; the body has changed form and has 

 considerably enlarged. All vermicular movement has stopped 

 at this phase of the evolution. 



Fig. 14. — Ulterior phase of development. 



