loo T- KOMAT : STUDIi:S OX TWO ABERRANT CTENOPHORES 



4. A pari of testis, showing •;perm-cells in various developmental stages; x6oo. 



5. Very young testis; x 500. 



6. Section including a series of sperin -receptacles; X160. 



7. Ovarv containing egg-cells in various developmental stages and seminal 

 receptacle containing spermatozoa; X36o- 



S. Apical region of testis ',\ith sperm duct; X400. 



9. \'erv yf>iing ovarv with cellular strand connecting epidermis and nvarial 

 iiicmlirane; X 500. 



10. Seminal receptacle, showing cross-section of tubular j)arl; X55'). 



11. Young ovary with seminal receptacle; X400. 



12. Peculiar kind of pigment-cells in fresh state; 420. 



13. Ordinary pigmcnt-cells in fixed and stained stale; X l4'>o. 



14. Sf> called rudiments of muscle-fibres; x 1400. 



Plate 6. 



All C. hocki. sketches in living state; X170, Fig. 4. X3oo. 

 I'ig. I. Unsegmented egg. 



2. First cleavage. 



3. Cleavage-head, showing spinning of plasm in superficial layer and radial 

 arrangement of granules in ectoplasm. 



4. 2-cell stage. 



5. 2-cell stage about to becoinc 4-cell stage; view from \egetative pole. 



6. 4-celI stage. 



7. 4-cell stage about to become 8-cell stage; side-view with animal pole above. 

 In all the following figures showing side-view of eggs in segmentation and gastrulation stages, 

 animal pole (micromere pole) is abo\e a:id vegetative pole (macromere pnle) l>elou. 



8. S-cell stage; side-view. 



9. the same; view from animal pole. 



10. i6-cell stage about to become 20-ceIl stage. 



1 1 . 24-cell stage about to become 28-cell stage. 



12. 28-cell stage; view from micromere (animal) pole. 



13. 32-cell stage about to become 40-cell stage. 



14. 56-cell .stage about to become 60-cell stage. 



15. .V stage during gastrulation, view from macromere (vegetative) pole; some 

 '•mesodermal" cells budded off from macromeres; also note the number of macromeres is 16. 



16. K stage during gastrulation nearly the same as, or somewhat more advanced 

 than, in the foregoing figure; view oblii|ue from micnimere pole. 



17. A stage during gastrulation, somewliat more adsanced than in llie preceding 

 figun;; view from micromere pole. 



18. Optical section of a stage directly after tJie closure of macromere pole; view 

 on lninsv(;rse plane. 



19. The same egg; o[)tical section, view from micromere j)ole, 'luadrate pore at 

 tiie Centre is th<: (i])ening on niicromcre pole, round ]iore of dotted line, llie oj)tical section of 

 axial space. 



20. A stage somewhat more ad\anced than in the |)receding ligurc, with an 

 opening on micromere jiole; side \iew. 



