ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 745 



Tadpoles with Strongly Developed Lips.* — 0. du Bois Reymond 

 describes tadpoles of Megalophrys from China, which protruded a yel- 

 lowish, triangular warty membrane in front of the mouth, and hung 

 from the surface with this expanded. 



Theodor Vogt t describes a tadpole from the region of Ruwenzori 

 with enlarged lips, with villus-like warts on the lower one. But the lips 

 are after the type of Rana temporary/, and not like those of Megalophrys. 



Luminous Organs in Fishes.:}: — Hiroshi Oshima has studied these 

 in Mmopterus (a Selachian), in Maurolicus (one of the Sternoptychidas), 

 and in various species of Myctophum (Myctophidas). 



In Etmopterus no numerical definiteness exists, the organs being 

 diffusely scattered, minute, epidermal swellings partly sunk in the cutis. 

 The photogenic body consists of a small number of conical photogenic 

 cells arranged radially into a hemispherical or semicylindrical mass. The 

 lens is unicellular. No unequivocal innervation has been proved ; the 

 blood-supply is carried on by a sinus underlying the organ. The light 

 produced from the organ is tranquil and faint, probably controlled by 

 special activity of pigment-cells. 



In the Sternoptychidsethe organs are definite in number and arrange- 

 ment according to species. They are complicated in structure, and 

 there is in some cases a system of intercommunication between the 

 internal parts of the neighbouring organs. The photogenic body is 

 formed by numerous polyhedral gland-cells filling the interior of the 

 organ in either regular or irregular arrangement. 



The lens is multicellular, and lenticular or flat in shape. The blood 

 capillaries form a network between the photogenic cells. The presence 

 of nerves has been proved in a few cases. The luminescence is not 

 momentary, but continuous. The light is not very intense. The photo- 

 genic body gives out light in air even when taken out of the organ. 



The organs of the Myctophidse are the most highly differentiated 

 forms of luminous organs. Some species present sexual differences as 

 regards their position on the body. The photogenic body consists of a 

 number of small lamellar gland-cells. The lens, if present, is formed 

 by a local thickening of the superposed scale. The photogenic body is- 

 richly supplied with nerves, and the blood-vessels form a plexus around 

 it. The spark -like light is rather bright, and is undoubtedly controlled 

 by nerves. 



In all the different forms of organ there is an abundant blood 

 supply, uniformity of structure in the species, glandular photogenic cells, 

 and a secretion product stainable with plasma-stains and never set free. 

 No spontaneous luminescence has been observed. In Myctophum where 

 the photophores, especially the large antorbital organs, have a spark- 

 like gleam when stimulated, the light may be quite useful for frightening 

 purposes. In Anomalops and Photoblepharon, the organs may be useful 

 for illuminating purposes, as they are placed inferiorly to the eyes and 

 emit quite intense and continuous light. There are no other instances 

 of this. 



* SB. Ges. Nat. Freunde Berlin (1910) No. 7, pp. 285-7 (3 figs.), 

 t SB. Ges. Nat. Freunde Berlin (1910) No. 7, pp. 287-9 (2 figs.). 

 X Journ. Coll. Sci. Univ. Tokyo, xxvii. (1911) art. 15, pp. 1-25 (1 pi. and 4 figs.) 



