12 Fisliery Board for Scotland. 



An interval of four to six hours in quiescent water has, however, 

 usualh^ been given to allow of the ova becoming fastened to the glass. 



The glass plates can be put into wooden boxes, each holding 

 about six plates. The boxes may be put in a herring barrel into a 

 frame, which can be revolved from time to time. The barrel would, 

 if necessary, be surrounded with ice during the railway journey'. 

 The spawn should be protected from the light. 



For the woodwork, I think cjal-tar is a suitable preservative. 



PLATE I. 



Fic. 1. Drawing ([ilan) of apparatus for conveyance of herring spawn. 

 ,, 1a. ,, (section) ,, ,, ,, 



,, 2. Drawing of apparatus in which the cooled herring spawn was kept 



during the Spring of 1911. 

 ,, 3. Enlarged drawing of part of embyro, to show ci-ystals in gut. 

 ,, 4. Live egg attached to dead egg, showing large number of crystals. 

 ,, 5. Enlarged drawing of crystal. 

 ,, 6. Enlarged drawing of anterior end of a larvsi, which had been retained in 



the egg until much of the j'olk had been aksorbed. 

 ,, 7. Enlarged drawing of a sperm. 

 ,, 8. Different shapes assumed by unfertilized eggs when they fell on the 



glass plate. 

 ,, 9. Drawing to show the corpuscle which alternately blocked and receded 



from the heart of the embryo partially shown in tig. 3. 

 ,, 10. Egg in which crystals had appeared within 36 hours of spawning. 



LETTERS USED. 



a. — Anus. 



er. — Crystal. 



de. — Dead egg, 



dm/. — Dorsal marginal fin. 



9^— Gut. 



le. — Live egsjr. 



nt. — Notochord. 



0. — Outer skin of zona. 



2)1. — Glass plate. 



t. — Tray. 



vmf. — Ventral marginal fin. 



yk. — Yolk. 



