398 REPOET OF THE COUNCIL. 



since been studied and a detailed report upon it, including a number of 

 illustrations of different stages in the life-histories of the fishes, is in 

 the press. 



Mr. Orton has continued to study the modes of feeding and the rate 

 of growth of invertebrates. The growth rate of many species has 

 been determined by fixing in convenient positions in Plymouth Sound 

 various objects, such as shells, tiles and pieces of wood, and measuring 

 the growth of the different animals which attach themselves to these 

 objects. Similar measurements have been made of animals growing on 

 marked objects put on the bottom in the Sound and subsequently 

 dredged up. The growth of many of these fixed species has been 

 shown to be surprisingly rapid, and frequently several generations may 

 be produced in the course of a year. A preliminary report on the 

 subject is in the press. 



The Director has continued his experiments upon the growth of 

 plankton diatoms under laboratory conditions, which have been referred 

 to in previous reports, and a paper on the subject is in course of 

 preparation. The Director has also been continuing his studies of the 

 marine annelids of the Plymouth area, and a number of new records 

 have been added to the local fauna. 



The trustees of the " Kay Lankester Pund," established by Mr, 

 G-. P. Bidder, elected Professor E. L. Bouvier of the Natural History 

 Museum at Paris as the first "Pay Lankester Investigator." Prof. 

 Bouvier arrived at the Laboratory in July and remained vintil the end 

 of August, the special object of his work being to study the life- 

 history of the sea-crayfish {Palinurus vulgaris). One of the most 

 interesting stages in the later larval development of this animal, the 

 imcrulm, which was known to occur in many foreign species of the 

 genus Palinurus, had never been observed in the case of the common 

 European form. This, as well as nearly all the earlier stages, was 

 obtained by pelagic fishing with the young-fish trawl in the neigh- 

 bourhood of the Eddystone. Prof. Bouvier also obtained specimens 

 of the interesting crustacean larva Trachelifer, which had not pre- 

 viously been recorded from the English Channel. 



Dr. Mortensen, of Copenhagen, worked during the summer at the 

 development of Echinoderms, and has published a paper in the Journal 

 of the Association containing descriptions of a number of larvae 

 belonging to this group, which he had obtained by fertilizing the eggs 

 and rearing the larval stages in the Laboratory. 



Some interesting experimental work on the electrical conductivity of 

 Echinus eggs was carried out by Mr. J. G-ray, and a preliminary 

 account of his experiments has been published in the Journal. 



