162 RICHARD ASSHETON. 



PLATE 13. 



Fig. 1.— Fertilised ovum. Rabbit 24^ hours, x 165. 



Fig. 2. — Ovum in two segments, from same rabbit as above. 24^ liours. 

 X 165. 



Fig. 3. — Ovum in two segments, showing great difference in size, from 

 same rabbit as above. 24i hours. X 165. 



Fig. 4. — Ovum in two segments, from rabbit 24 hours. Polar bodies sepa- 

 rated. X 165. 



Fig. 5. — Ovum in two segments, from rabbit 254 hours ; drawn after mount- 

 ing in Canada balsam. X 165. 



Fig. 6. — Embryo in four segments, from same as preceding. 25^ hours. 

 X 165. 



Fig. 7. — Embryo in five segments. 27i hours. X 165. 



Fig. 8. — Embryo in eight segments, x 165. 



Fig. 9. — Embryo in eight segments. X 165. 



Fig. 10. — Embryo in seven segments. X 165. 



Fig. 11. — Embryo in eight segments, showing internally-placed polar 

 body. 39 hours. X 165. 



Fig. 12. — Embryo of 47th hour, showing contrast in size of the several 

 segments (seventeen segments). X 165. 



Fig. 13. — Isolated segments of same specimen (47th hour), x 165. 



Fig. 14. — Embryo (27i hours) in seven segments. 



PLATE 14. 



Fig. 15. — Embryo (66| hours), showing great difference in size of seg- 

 ments. 



Fig. 16. — Section of a specimen preserved in silver nitrate j per cent. ; 

 stained picro-carmine, and cut in paraffin. 72 hours, x 465. 



Fig. 17- — Embryo, showing contrast in size of segments. 



Fig. 18. — Section of embryo (72 hours) preserved in Perenyi ; stain, borax 

 carmine. 



Fig. 19. — Another section of the same embryo. Both showing what might 

 be a van Beneden blastopore, but on opposite sides ! 



Fig. 20. — Section through rabbit embryo of the 47th hour. Cut in paraffin. 

 Preserved i per cent, silver nitrate 2 minims, water and sunlight y hour ; no 

 other stain, x 465. 



