of that family. The presence or absence of discs on the ends of fingers and 

 toes indicates cHmbing abiHty or lack of it. The Acris and Pseudacris groups 

 have this structure much reduced, so it pays to use a hand lens in examining 

 fingers and toes on small frogs. These toe discs are circular in the Hylidae, 

 transversely oval in most of the Lel^todactylidae. The amount of webbing is 

 fairly well correlated with habitat. It oftens calls for close examination to 

 determine the particular toe joint to which the web extends. 



Beginners sometimes fall into error when femur or tibia is to be examined. 

 It should be remembered that the femur is the section of the hind leg nearest 

 the body, the tibia (or tibio-fibula) the second, and that the third segment, 

 sometimes mistaken for the tibia, is an elongated section of the tarsus or ankle. 



TADPOLES 



The identification of tadpoles is rather difficult and should be undertaken 

 by the beginner only when mature tadpoles — with hind legs but without visible 

 fore legs — are available. At that stage the epidermal teeth around the mouth 

 are at their best stage of development and their examination under a lens will 

 reveal their shape and arrangement. A knowledge of the habitat and life 

 histories of local frogs will be of considerable aid. For example, the tadpoles 

 of wood frogs would almost always be found in temporary ponds, while tad' 

 poles of green or bullfrogs would rarely be found except in permanent ponds. 

 Size differences and differences in time of metamorphosis also are of much aid 

 in the identification of tadpoles. A collection of mature tadpoles, complete 

 with data on habitat and time of collection, would be of much value to research 

 workers. 



EGGS 



Time of year, place and manner of deposition of eggs, and the number 

 and arrangement of the jelly membranes are all useful in identification. The 

 excellent descriptions and illustrations by the Wrights should be carefully 

 studied. For later study, eggs are best fixed in Smith's fluid, which keeps both 

 egg and membranes in good condition. Freshly laid eggs should be used, if 

 possible, as the jelly layers become less distinct as the egg develops. Smith's 

 fluid consists of 



Potassium bichromate 0.5 grams 



Formalin (comm.) 10.0 cc. 



Water 87.0 cc. 



Glacial acetic acid 2.5 cc. 



The acetic acid should not be added much before the fixative is to be used, 

 as it may cause some deterioraticMi of the fluid during storage. The eggs should 

 be fixed in this fluid for 24 hours, washed in running water for 6 hours, and 

 then put in 3 or 4% formalin (not stronger) for storage. The formalin should 

 be changed at intervals until it no longer becomes discolored. 



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