262 CLAP P. 



EXPLANATION OF PLATE XIX. 



Fig. 14. A horizontal section of an Acanthias embryo 17 mm. long, showing 

 the growing point of the lateral line with its " pocket " and the nerve. Cam. 

 Z. 16, DC. 3. 



Fig. 15. Drawn from a preparation of the skin, showing the appearance of 

 the cells of the organs at an early stage of their development; Cam. Z. 4, oc. 3. 



Fig. 16. A vertical section through a sense organ, showing the relation of the 

 connecting strand to the organ. Cam. Leitz 7, oc. 3. 



Fig. 17. Preparation of skin showing the appearance of the rudiment of the 

 lateral line organs with its enlarged growing end. Cam. Z. 4, oc. 3. 



Fig. 18. A horizontal section of an embryo of Batrachus 7 mm. long, show- 

 ing the position of the growing point of the line in its relation to the outer layer 

 of ectoderm and to the muscles. Cam. Z. 16, oc. 3. 



Fig. 19. View of same magnified. Cam. Z. 4, oc. 3. 



Fig. 20. Cross-section through the enlarged portion of the line. Cam. Leitz 

 7, oc. 3. 



In Fig. 16, for tn read n. 



