Fig. 



4. 



Fig. 



4a 



Fig. 



5. 



Fig. 



6. 



Fig. 



7. 



Fig. 



8. 



Fig. 



9. 



936 PROFESSOR W. C. M'INTOSH AND MR E. E. PRINCE ON 



Fig. 3. Gadiis ceglefinus, section through the blastoderm at the morula stage, 22nd hour, March 25, x 175 



1886, . . . . . . . . xl75 



„ ,, surface view of the edge of the blastoderm and periblast, 26th hour, March 



30, 1886, . . . . . . . x 175 



. „ ,, surface view of the same, 2 hours later (28th hour), . . x 175 



T. gurnardtis, yolk pitted by periblastic nuclei, viewed obliquely from above, . x 90 



„ periblast and edge of blastoderm, May 26, 1886, . . . . x 415 



,, similar view, 8th hour, June 25, 1886, . . . . x 156 



„ similar view, 8th hour, May 26, 1886, ..... x 415 



Gastrosteus spinachia, part of rim and of blastoderm when extended about nine-tenths over 



the yolk-surface, . . . . . . . . x 130 



Fig. 10. G. oegleftnus, section through the invaginated rim when almost at the equator, 4th day, and 



no germinal cavity present, ........ x 435 



Fig. 11. Ovum of Solea vulgaris, showing chromatophores over the yolk and groups of oil-globules 



segregated under the embryo, . . . . . . . x 50 



Fig. 12. Ovum of Gastrosteus spinachia in the morula condition, May 9, 1886 : x, facets of attach- 

 ment to adjacent ova, . . . . . . . . x 25 



Fig. 13. Newly-hatched larva of Glupea sprattus, . . . . . . x 21 



Fig. 13a. Larva of Glupea sprattus, stage (in a somewhat abnormal specimen with minute papillae 

 behind and below eye, and on the anterior surface of abdomen) more advanced than in 



the preceding figure, . . . . . . . . x 12 



Fig. 14. T. gumardus, May 24, 1886. Three oleaginous spheres were present in this ovum, . x 55 



Fig. 15. a, b, c, d, e, Pleuronectes flesus, vertical sections through the blastoderm on the 3rd day, 



April 7, 1886 : a, through the middle of the germ ; c through the marginal part, . x 150 



Fig. 16. Ovum of Gadus wglefinus, marginal blastodermic cells sending out filamentous protrusions 



under pressure, ......... x 230 



Fig. 17. Gadus aglefinus, vertical section through an ovum with the rim nearly at the equator; no 



germinal cavity appears, 4th day, March 24, 1885, . . . . x 64 



Fig. 18. Ovum of Gadus ceglefinus, vertical section through the blastoderm at the 2-cell stage; many 



vesicles are collected at the base of the blastomere, ..... x 435 



Fig. 19. Ovum of the haddock on the 3rd day, at 10 a.m., viewed from above, . . x 30 



Plate III. 



1. T. gumardus of the 3rd day, transverse section through the cephalic region, . . x 175 



of the 3rd day, transverse section posterior to fig. 1, . . . x 175 



of the 3rd day, transverse section through the terminal portion of trunk 



(primitive streak 1), ....... x 175 



of the 9th hour, May 28, 1886, cephalic end of embryo, . x 225 



of the 3rd day, May 27, 1886, snout of embryo, . . . x 250 



of the 72 nd hour, snout of embryo, ...... x 250 



of the 6th day, March 29, 1886 (Kupffer's vesicle and blastopore), . . x 400 



of April 26, 1886, 10 a.m., end view, . . . . x 250 



of April 26, 1886, somewhat later than fig. 8, end view of early embryo, . x 250 



of April 26, 1886, 11.40 a.m., . . . . . x 250 



of April 26, 1886, 12.45 noon, . . . . . x 250 



of May 1886, side view of blastopore and neurenteric canal, &c, . . x 97 



of May 1886, side view of blastopore and neurenteric canal, &c, . x 97 



of May 25, 1886, transverse section through the trunk (rim at equator), . x 175 



transverse section through the caudal region (primitive streak 1), same stage 



as fig. 11, . . . . . . x 175 



Fig. 13. „ of May 26, 1886, transverse section through the trunk (rim past equator), . x 175 



Fig. 14. G. morrhua, of April 26, 1886, Kupffer's vesicle viewed through the transparent embryo, x 150 



Fig. 



1. T. 



gurnardu 



Fig. 



2. 



)> 



Fig. 



3. 



)> 



Fig. 



4. 



ii 



Fig. 



5. 



j) 



Fig. 



6. G. 



ceglefinus, 



Fig. 



7. 



>) 



Fig. 



8. G. 



morrhua, 



Fig. 



8a. 



» 



Fig. 



86. 



>> 



Fig. 



8c. 



)> 



Fig. 



9. 



)> 



Fig. 



10. 



)> 



Fig. 



11. G. 



asglefinus, 



Fig 



12. 



ii 



