EXPLANATION OF PLATE XXIX. 

 FIG. 



1-2. BURSARIA TRUNCATELLA, Muller. i, Adult animalcule, x 50; 2, supposed 

 young condition, x 200 (Stein). 



3. BALANTIDIUM ENTOZOON, Ehr. sp., x 100 (Stein). 



4. NYCTOTHERUS CORDIFORMIS, Stein, x 150. an, anal aperture (Stein). 



5. NYCTOTHERUS VELOX, Leidy, x 200 (Leidy). 



6-9. METOPUS SIGMOIDES, Clap. & Lach. 6 and 8, Extended, 7 and 9, spirally 

 contorted animalcules, x 200 (Stein). 



10. PLAGIOTOMA LUMBRICI, Duj., x 200 (Stein). 



11. CONDYLOSTOMA STAGNALIS, Wrz., x 150. u, Undulating membrane (Wrzes- 



niowski). 



12. CONDYLOSTOMA PATENS, Miill. sp., x 150 (Stein). 



13, 14. SPIROSTOMUM AMBIGUUM, Ehr. 13, An extended, 14, a spirally contorted 

 zooid, x 1 50 (Stein). 



15. BLEPHARISMA UNDULANS, Stein, x 150. u, Undulating membrane (Stein). 



16, 17. BALANTIDIUM COLI, Malmsten sp., x 200. At 17 an example preparing to 

 divide by transverse fission, and having already developed at p 2 a second 

 peristome (Stein). 



1 8. LEUCOPHRYS VIRENS, Ehr. sp., x 150.^, pharyngeal passage (Stein). 



19, 20. FOLLICULINA STYLIFER, St. Wrght. sp. In each instance the anterior region of 

 the lorica is alone represented, the peristome lobes of the contained animal- 

 cule in Fig. I9being fully expended, while in Fig. 20 they are entirely with- 

 drawn, leaving the stylate appendage only projecting beyond the orifice of 

 the lorica. Dimensions unrecorded (Strethill Wright) 



21-28. FOLLICULINA AMPULLA, Muller sp. 21 and 22, Entire animalcule and distal 

 region of peristome of var. ACULEATA, Clap, and Lach. ; at 24 numerous 

 examples crowded on a shell of Spirorbis nautiloides, x 20 ; 25-27, 

 examples showing the diverse plans of ornamentation of the lorica; 28, 

 normal type in its fully extended state, x 200 (Stein). 



29-32. FOLLICULINA PRODUCTA, St. Wrght. sp. 29, Adult animalcule in its full; 

 extended state, x 200 ; 30-32, embryonic condition (Strethill Wright). 



33-35. FOLLICULINA ELEGANS, Clap. & Lach. sp. 33 and 34, Adult animalcules, 

 ventral and lateral aspects, x 200 (Stein) ; 35, empty lorica showing at v 

 valvular elements (Clap. & Lach.). 



36. FOLLICULINA BOLTONI, S. K., x 200. 



37, 38. CH^ETOSPIRA MUELLERI, Lachmann, extended and partially retracted states as 

 observed by the author, x 300. 



39. FOLLICULINA HIRUNDO, S. K., x 200. 



40. FOLLICULINA AMPULLA, Muller sp., var. VIRIDIS, St. Wrght., x 1 50 (Strethill 



Wright). 



