DEPARTMENT OF MARINE BIOLOGY. 165 



from creeping out, permitting the formation of dew within. A young speci- 

 men of Cerion viaregis and of Cerion incanum, the former gathered from the 

 planting at the south end of Loggerhead Key and the latter at Key West, 

 were placed in each of cages 1 to 44. In cage 45 a colony of 77 young Cerion 

 incanum was placed, while cages 47 to 56 contain the following combinations: 



No. 47 contains 25 C. incanum and 25 C. viaregis. 



No. 48 contains 25 C. incanum and 25 C. casablancase. 



No. 49 contains 25 C. incanum and 25 C. uva. 



No. 50 contains 25 C. incanum and 25 C. crassilabre. 



No. 51 contains 25 C. viaregis and 25 C. uva. 



No. 52 contains 25 C. viaregis and 25 C. crassilabre. 



No. 53 contains 25 C. casablancse and 25 C. uva. 



No. 54 contains 25 C. casablancse and 25 C. crassilabre. 



No. 55 contains 25 C. uva and 25 C. crassilabre. 



No. 56 contains 25 C. viaregis and 25 C. casablancse. 



A new cage was made, the walls of half of which were covered with wire and 

 the other half with cheese cloth. In each of these a colony of cerions was 

 placed, and in both the top was left open, excepting a fringe of wire to prevent 

 the escape of the specimens. Thus it is hoped to determine whether by any 

 chance the attachment of the mollusks to the wire meshes of the side of the 

 cage may have a killing influence, possibly through the heating of the wires. 



On May 23 a colony of 500 each of marked specimens of Cerion viaregis 

 and C. incanum was planted in a small, low meadow at the east end of Man 

 Key and another of equal numbers in a similar location on the north end of the 

 little key to the east of Man Key, which may be called Boy Key. Both these 

 colonies are marked with stakes. These two plantings were made with the 

 hope of duplicating the hybrid conditions on Newfound Harbor Key, thus 

 materially reducing the danger of losing these experiments through fire, which 

 is always a menace to our work on these keys. 



Birds of the Florida Keys. 



During Dr. Bartsch's stay at the Tortugas, the Navy Department, under 

 the direction of the Biological Survey at Washington, moved the warden's 

 house on Bird Key. This change necessitated the moving of 2,420 tern eggs 

 which were on the point of hatching. These eggs were placed in nests adjacent 

 to the region laid bare by the moving, and in no instance did the birds, upon 

 whom an extra egg had been bestowed, refuse to assume the duty assigned. 

 Very little damage was therefore done in the moving, but probably an increase 

 of young occasioned, because the robbed parents soon replaced the lost egg 

 and reoccupied the territory temporarily laid bare by the activities of the 

 artisans. 



Dr. Bartsch reports the need for shade trees or shrubbery to protect the 

 young birds from the glaring rays of the sun, the vegetation having mostly 

 been carried off by recent hurricanes. 



Study of Luminous Crustacece and Fishes in Vicinity of Miami, Florida, 



by Ulric Dahlgren. 



In the latter part of January, Dr. Dahlgren went to Miami, Florida, to 



study the luminous crustacese and fishes. The principal object was to find a 



species of Cypridina that gave a greenish or yellowish light that might be 



used in Dr. Harvey's chemical work for experiment with the blue-light form 



