368 DENDRITIC APPENDAGE OF UROGENITAL PAPILLA 



is true that J. Brock '^ made a microscopical study of the appendnge 

 in question in Plotosiis anguiUaris (Bloch) Lacep., l)ut as his niateri:ils 

 Avere confined to four immature specimens, the results of his investiga- 

 tion were not entirely satisfactory. 



Last year, at the suggestion of my friend Mr. T. Kitahara, 

 I undertook a new investigation of the appendage in Plotosus 

 cmguillaris already studied by Brock. This fish is easily obtainable at 

 the Marine ]jiolo2;ical Station at Misaki throuo-hout all seasons, so that 

 the supply of my materials was practically unlimited, and I was able 

 to examine the organ in a large number of fresh as well as alcoholic 

 specimens of both males and females in various stages. The following 

 notes containing the results of my investigation are, 1 regret to say, 

 purely morphological, but it is hoped tliat they may throw some side 

 light on the physiological function of the organ, for the determination 

 of which future research is however still needed. 



Before going further, I wish to express m}^ deepest indebtedness 

 to Prof. Dr. MiTSUKURi for kind supervision of my work and to Mr. 

 T. Kitahara for valuable advice. 



External Paris. 



As a full description of the external parts of the appendnge seems 

 at the present day hardly needed, I shall introduce here only sucli 

 remarks on the general features of the organ as will make what 

 folloAvs intelli^-ible alonîj with others about it in its fresh state and in 

 its early stages. 



Fig. 1, PL XXXVI. represents in their natural size the 

 appendage and the adjacents ])arts in a. fully grown individual. 



1) Brock, J., Ueber Anhangsgebilde des Urogenitalapparates von Knochenfischen. Zeit. f. 

 ïviss. Zool. Bd. 45, 1S87. 



