PLATE 50.— Various Objects, 



Figure 



1. Chlorogmium euchlorum, E., undergoing oblique division. 



2. Elements of the chyle, a, molecules; b, free nuclei ; c, chyle-corpuscles; d, one of 



the same with processes. 



3. Coccudina costata, I). 



4. Anystis ruricola. 



5. Bacilli and cones of the retina of animals, a, /3, from the pigeon, a, bacillus ; a, pro- 



per bacillus ; b, its pale inner extremity ; c, line of demarcation at the boundary of 

 the bacillar layer ; d, corpuscle of the outer granular layer. (3, cone ; o, as above ; 

 e, bacillus of cone ; f, proper cone ; g, globule of fat in the same ; h, expansion of 

 cone, y, from the frog, letters as above. S, from the perch, letters as above ; i, part 

 at which the cone usually breaks off; k, radial fibre ; /, expansion of inner granular 

 layer, e, twin cones. 



6. Frustulia membranacea. a, valve ; b, front view of frustule, 



7. Emydium testudo. 7 a, isolated style ; 7 b, claw of leg. 



8. Macrobiotus Hufelandii ; X ovary. 8 a. (Esophageal bulb ; X its framework. 



9. Milnesium tardiyrada. 9 a, pharynx, with + internal buccal lobes, and f styles ; 9 b, 



right posterior leg, seen from beneath. 



10. Eucampia zodiaea. 



11. Halteria yrandinella, D., seen from above, 



12. Halteria yrandinella, D., side view, 



13. Kerona polyporum, E, 



14. Gyyes yranulum, E. 



15. Lacinularia socialis, E. ; 15 a, the same, more magnified, 



16. Mask (labium) of JEschna (Libellulid^e), 



17. Spermatozoa of Triton cristatus. 



18. Sarcolemma of muscle, twisted, 



19-24. Navicula amphirhynchus in conjugation. Fig. 19, side view of valve of parent 

 frustule ; 20, frustules in an early stage of conjugation ; 21, sporangial sheath ; "22, 

 sporangial sheath Avith parent frustules attached; 23, sporangial frustule (front 

 view), with sheath and one parent frustule ; 24, side view of sporangial sheath. 



25. Spermatozoa, human ; one exhibiting the so-called spermatozoal membrane. 



20. Spermatozoa of rat (Mus rattus). 



27. Spermatozoa of field-mouse (Arvieola (Hypudaus) arvalis). 



28. Spermatozoa of rabbit (Lepus cuniculus). 



29. Spermatozoa of goldfinch {Frinyilla (Carduelis) elegans). 



30. Spermatozoa of blackbird (Turdus meruld). 



31. Spermatozoa of wood-shrike (Lanius rufus), 



32. Spermatozoa of a Coleopterous Insect. 



33. Spermatozoa of frog (liana temporarid). 



34. Spermatozoa of perch (Percajluviatilis). 



35. Spermatic cyst of rabbit, with five globules, a, separate globule. 



36. Spermatic cyst of rabbit, the cells or globules containing each a sp3rmatozoon. 



a, separate globule. 



37. Spermatic cyst of the common creeper (bird, Certhia familiar 'is), containing a bundle 



of spermatozoa. 



38. a, b, c, Staurostra construens, E. 



39. JBiblariutn crux (leplostauron), E. 



40. Goniothecium yastridium, E. 



41. Periptera chlamidophora, E. 



42. Periptera chlamidophora , E. 



43. Aulacodiscus crux, E, 



44. Goniothecium odontella, E, 



45. Actiniscus sirius, E. 



46. Rhizoselenia americana, E, 



47. Chcetoceros didymus, E, 



