lO 



NATURE 



[July 7, iqio 



MARINE BIOLOGICAL PHOTOGRAPHY. 



THOUGH year by year photography plays a 

 greater part in the illustration of works on 

 natural history, marine biology does not appear to 

 have received its full share of attention from the 

 scientific photographer. 



It can be claimed for photography that it is an 

 accurate and rapid method of making marine biologi- 

 cal records. The rapidity admits of the recording of 



—Young Thornback R.iy. 



delicate structures during life, thus avoiding the 

 opacity and distortion that so soon follow death; but 

 the main advantage lies in the fact that by means 

 of photography the number of workers making 

 records can be greatly increased. Expert biologists 

 who have the time to make drawings of minute 

 structures are distinctly limited in number, whereas 

 the photographer with but a general biological know- 

 ledge is able to make accurate and useful records 

 of structures, possibly quite new to him, and 

 many points of wliich he miglit miss were he 

 to draw them. 



In order to derive the full advantages 

 offered by photography, the worker must be 

 prepared, in addition to illustrating minute 

 structures, to deal with the habits, move- 

 ments, characteristic postures, and general 

 external appearance of any particular marim 

 animal. Such records should preferably bi 

 made in natural environments, but, failini; 

 this, in special tanks. 



Prof. Reighard, in his contribution " Photo- 

 graphy of Aquatic Animals in their Natural 

 Environments," describes very fully sub- 

 aquatic photography and photography with 

 the camera above water. Subaquatic photo- 

 graphy, however, has a very limited applica- 

 tion, mainly in consequence of the want of 

 light, and for obtaining details of external structure 

 is not nearly so satisfactory as photography in special 

 tanks. 



With the camera above water the main difficulty to 

 be overcome is due to the photograph having to be 

 taken llir<Hit;h two media, air and water, for the 

 light reflected from the surface of the water, being 

 t,'reater than that reflected from the object to be 

 photographed, the desired image is obscured in the 

 NO. 2123, VOL. 84] 



general fogging of the photographic plate. When 

 photographing a submerged object with the camera 

 directed at an angle to the surface of the water, this 

 reflection from the water can be avoided by holding 

 a screen at a suitable angle immediately above the 

 object. 



When taking a photograph directly aibove the 



object, the light must be cut off above the camera. 



The illustration of a young thornback ray was taken 



in 8 inches of water, with a golf umbrella held over 



the head of the operator. 



For tank work the most useful 

 arrangement is a tank about 3 feet 

 long, 2 feet high, and 6 to 8 inches 

 from front to back, the bottom and 

 sides being of wood, the front and 

 back of j-inch plate-glass. Inlet and 

 outlet pipes pierce the sides, and there 

 must be arrangements for a constant 

 supply of sa,ly|ar fresh water which 

 can be sent tOTKfgh the tank at will. 

 The specimen placed in the tank 

 usually sulks at the bottom ; if, after 

 a time, the water is suddenly turned 

 on, the fish or other creature heads up 

 to the stream, and a snapshot can be 

 taken in a natural position. For the 

 above work it is desirable to use a 

 reflex camera with a rapid lens of not 

 less than 8-inch focal length. 



For the photography of compara- 

 tively small and microscopic marine 

 objects a sp&cial apparatus is neces- 

 sary. I use a portable apparatus with 

 which it is possible to take a photo- 

 graph of a specimen in a horizontal or 

 vertical position, by transmitted or re- 

 flected light, and by means of a mirror 

 to see the object up to the last moment before expo- 

 sure, so as to ensure a living specimen being photo- 

 graphed in a suitable position. There is also a fixed 

 stage upon which a specimen can be placed in a tank 

 or cell, and a photograph taken of any desired magni- 

 fication without moving the specimen. 



When photographing from life-size up to 25 mag- 

 nifications I use lenses of 6-inch, 32-inch, and 35-mm. 

 focal lengths, on a camera having an extension of 



Fir,. 2.— Whelk feeding on Crayfish. 



36 inches without a microscope. For higher mag- 

 nifications I drop a microscope into the apparatus, 

 and get any desired magnification up to 2600 with a 

 I /12-inch oil immersion. 



The exceptional length of bellows extension is 

 necessary in order to obtain a high degree of mag- 

 nification from a lens of comparatively long focus, 

 thus ensuring all parts of the specimen being in focus 

 at the same time. 



