208 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



the outside of the egg membranes, and thus increasing 

 their specific gravity beyond the point capable of floating 

 in the water. On several occasions when the supposed 

 dead embryos were examined, it was found that they were 

 alive, and, on the removal of the coating of fine mud, the 

 embryos again floated freely on the surface of the water. 



" Towards the close of the hatching experiment, the 

 water was passed through an ordinary flannel jelly bag 

 before being allowed to enter the tanks, and by this 

 means it was found possible to entirely remove the 

 suspended matter, the water passing into the various 

 vessels in a perfectly transparent condition ; but, owing 

 to the lateness of the season, and the arrival of workmen 

 to make the necessary alterations for converting the pre- 

 mises into our present hatchery and laboratory, no further 

 hatching could be tried with the filtered water. 



" Besides the fish hatching experiments now described, 

 other investigations were carried on as well, and these 

 included visits made from time to time to the various 

 shell-fish beds in the neighbourhood, for the purpose of 

 examining their condition and collecting samples for 

 working at in the laboratory and for testing the water in 

 the tanks. "We had, therefore, many economic marine 

 animals living satisfactorily in the tanks during the two 

 months ; these consisted of various kinds of fishes, includ- 

 ing small Soles, Plaice, and Dabs ; shell-fish, including 

 Mussels and Cockles, and also a couple of Oysters found 

 living in the vicinity ; Crustacea, including Shrimps, 

 Lobsters, and Crabs, and other invertebrates which, 

 although not directly valuable, are yet indirectly so, from 

 the part they play as the food of other marine animals. 

 Many of the Shrimps were egg-bearing females, and the 

 more mature ones were taken from amongst the others 

 and kept in separate vessels ; so on several occasions we 



