1891.] 



TADPOLES OF THE EUROPEAN BATRACHIANS. 



599 



pi. V. fig. 7), and in Pelodytes by Bedriaga (Bull. Soc. Nat. Mosc. 

 1889, p. .')4i). Their aspect is shown in the following figures, 

 representing much-enlarged pieces of the upper caudal crest of 

 Pelodytes and Discoglossus. 



Fig. 4. 



A 



B 



Much enlarged pieces of upper caudal crest of, A, Pelodytes punctatus, 

 B, Discoglossus pictus. 



Preservation and Manipulation. — Tadpoles should be preserved in 

 alcohol. Chromic acid is not to be recommended, as rendering 

 the specimens too brittle for ordinary study. To ensure the good 

 condition of specimens preserved in spirit, it is necessary to treat 

 them with a little care ; tadpoles thrown into the ordinary collecting- 

 bottle promiscuously with other specimens are never in a satisfactory 

 condition for display in a collection and for future study. The best 

 plan is to provide one's self, when going out collecting, with small 

 test-tubes half-full of weak spirit ; the tadpoles, when taken out of 

 the fishing-net, should be dipped head foremost in the tube, which 

 may be filled with as many specimens as it will hold. On reaching 

 home, say two or three hours later, the liquor should be at once 

 changed to strong spirit (40°), which will again require changing the 

 next day, and so on until it ceases to be strongly coloured. By this 

 method, of killing in weak spirit and then seizing by strong spirit, 

 the tadpole preserves its natural shape in a remarkably perfect 

 manner, and the delicate caudal crests do not shrivel. Specimens 

 which have been only a few hours in spirit are in the best condition 

 for study ; a slight pressure of the fingers on the back and breast 

 causes the beak and lip to gape fully, showing the arrangement of 

 the labial papillae and teeth. When studying specimens which have 

 been a long time preserved, it is best to soak them for a few minutes 

 in water, which, penetrating the subcutaneous vacuities, swells them 

 out and restores their Hfe-appearance. Tadpoles should never be 

 allowed to remain out of the liquid, as they very rapidly shrink, 

 especially the caudal crests. The lines of muciferous crypts are 

 sometimes very difiicult to trace. Heron Royer (Bull, Soc. Et. 



