Morone labrax. Linn. Bass.

Towards the end of May a large female bass in one of the Aquarium tanks appeared to be approaching ripeness, and constantly swam round the tank followed by one or more of its companions, probably of the opposite sex. A fine-meshed net was accordingly placed over the overflow from the tank in question, and on the morning of the 29th May was found to contain a very large number of eggs, undoubtedly attributable to this species, the only other Teleostean inmates being turbot, congers, pollack, rocklings, and two species of wrasse.

All the eggs proved to be unfertilised, or, at most, showed only an approach to segmentation, which may have been due to the spermatozoa of a rockling. Circumstances seemed strongly to point to the fact that the eggs are not all shed at once, but owing to an unfortunate series of accidents with the net it is impossible to speak on this point with absolute certainty.

Although the bass is a common British fish, its ova find no place in the records of British naturalists, and are only known from the descriptions of Raffaele, who obtained them both from parents living in the tanks of the Naples Laboratory and from the neighbouring sea.

The eggs observed by us at Plymouth are spherical, and, while living but unfertilised, measure from 1·25 to 1·34 mm in diameter. Raffaele gives 1·155 to 1·2 mm as the diameter of Naples examples. The latter have an oil-globule of ·332 to ·366 mm.