Further observations on the nervous system of the American leopard frog (Rana pipiens) compared with that of the European frogs (Rana esculenta and Rana temporaria) / Henry H. Donaldson.

  • Donaldson, Henry Herbert, 1857-1938.
Date:
1910
Catalogue details

Licence: In copyright

Credit: Further observations on the nervous system of the American leopard frog (Rana pipiens) compared with that of the European frogs (Rana esculenta and Rana temporaria) / Henry H. Donaldson. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    three weeks after the assumed maximum, and at a time when the seasonal weight has begun to diminish. Here the difference is less than in the case of the esculenta, but is susceptible of a similar explanation. The relation of these two series of observations can be conveni- ently shown in still another way. I have been able to point out (Donalsdon ’02) that a fairly accu- ate determination of the weight of the central nervous system in frogs can be made by the formula C. N. S. = (Log. Bd. W. C where C. N. S. is the weight of the central nervous system, Bd.W. the body weight in grams, L the total length in mm. and C. a constant to be determined for each species. Since publishing this formula I have found that the most convenient way of expressing seasonal variations on the weight of the central ner- vous sj^stem is by the variations in C. Applying this method to the series before us, and remembering that the increase in the relative weight of the central nervous system is measured by the increase in C, and vice versa, we obtain the following: TABLE 11 To show the values of “ C” for each of the several series AVERAGE BODY WEIGHT R. pipiens 1904 \ Average of 12 records / 2<S. 0 VALUE OP C. 26.2 R. esculenta 1904 Average of 8 records First “weight group” omitted R. esculenta 1909 Average of 9 records Last “ weight group ” omitted J R. temporaria 1904 \ * Average of 12 records / R. temporaria 1909 ) Average of 16 records j 32.4 24.6 33.1 23.0 Difference 1.6 24.6 22.8 26.8 21.9 Difference 0.9