L96 CARNEGIE INSTITUTION OF WASHINGTON. 



REPORTS OF INVESTIGATORS. 



Luminosity in Marine Animals, by Ulric Dahlgren. 



The writer has been engaged in researches into the hghting powers of 

 animals. One paper is nearly ready on the luminous powers of Cypridina 

 hilgendorfi and a number of allied ostracods, mostly marine. The luminous 

 organs are shown to consist of an enlargement and specialization of the dermal 

 glands so characteristic of the group, and especially those on the upper lip, 

 which in many forms have had the more primitive function of salivary glands. 

 In Cypridina an interesting fact, hitherto unnoticed, is that one lobe of the 

 gland on each side extends far past the middle of the animal's body, thus 

 invalidating certain physiological work in which the cutting of the animal's 

 body in two halves was supposed to divide it into a luciferin-bearing and a 

 non-luciferin-bearing portion. In another light-bearing Pyrocypris, from the 

 East Indies, a more primitive but efficient organ has been described. 



Further work on fishes confirms Harvey's discovery that in some fishes 

 luminous bacteria in the light organ are the principal source of the light. 

 Measures to secure a number of deep-sea luminous fishes have been under- 

 taken, but the time is not yet ripe for results. 



Further Studies on Bioluminesccnce, by E. Newton Harvey. 



During the autumn and winter of 1920 the author continued his studies on 

 light production in the animal kingdom with two objects in view: first a 

 search for new sources of luciferin, the material oxidized by luminous animals 

 in the presence of a catalyst, lucif erase; second, a study of the specificity of 

 luciferin and luciferase. A trip was made to the Banda Islands of the Dutch 

 East Indian Archipelago, where two fishes with very large luminous organs 

 are found. Studies were also made at the Puget Sound Biological Laboratory 

 at Friday Harbor, Washington; on the Dutch fisheries steamer Brak, off 

 Batavia, Java; and at the Musee Oceanographique, Monaco. It gives me 

 pleasure to acknowledge the kindness of Professor T. C. Frye, director of the 

 Puget Sound laboratory. Dr. A. L. J. Svmier, director of the Batavia Fisheries 

 Station, and Dr. J. Richard, director of the Mus^e Oceanographique, Monaco, 

 during my stay at these places. 



Many luminous forms new to the author were obtained, including Polynoe, 

 Tomopteris, Odontosyllis, various medusse and ctenophores, Pyrocypris, 

 Geophilus, Pyrosoma, and two fishes. Some of these forms were rare, but 

 others occurred in sufficient numbers to determine whether the luciferin of one 

 species would luminesce with the luciferase of another, and vice versa. This 

 study on specificity is still being continued and a preliminary paper will 

 appear shortly. It will suffice to say now that the lucif erin-lucif erase reaction 

 appears to be specific to a high degree. Only if the luciferin and luciferase 

 come from closely related forms will they luminesce when mixed. Odonto- 

 syllis promises well as a source of material and Tomopteris will give the answer 

 to some interesting problems in connection with the color of the light, if it 

 can be obtained in sufficient quantity. 



The marine fishes Anomalops and Photoblepharon of the Banda Islands were 

 obtained in large numbers and physiological studies were made. Although 

 not suited for the preparation of large quantities of luminous material, the 

 organ of these forms turns out to be of extraordinary interest for a quite un- 

 looked-for reason. Despite the general appearance of an organ of external 

 secretion, no luminous material is excreted to the sea-water by the living fish. 

 If the organ is tested in sea-water and examined under the microscope, 



