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Show 1873.] THE RED BLOOD-CORPUSCLES OF BATRACHIANS. 163 the subject, this will not be attempted at present. Only I remember that Rudolph Wagner long since discovered the large size of the red blood-corpuscles of Proteus, and Van der Hoeven soon afterwards their almost equal magnitude in Cryptobranchus japonicus, that Riddel quite recently proved their preeminent largeness in Amphiuma, and that they were originally examined and measured and their Batrachian character shown by m e in Lepidosiren. Of some of the animals mentioned in the present Table, the blood-corpuscles, so far as I know, have not been previously examined. Lepidosiren is here placed among the Batrachians, not to imply any view as to its true position, but merely because this paradoxical creature has blood-disks like in size to those of a Batrachian, and unlike, in this respect, to those yet known of any regular fish. Cryptobranchus japonicus is the same as Sieboldia maxima of the following Table, and of some of the former ' Proceedings' of the Society. Table of Measurements of the Red Blood-Corpuscles of Batrachians. According to m y invariable practice, all the measurements are expressed in vulgar fractions of an English inch ; and of the corpuscles the long diameter is denoted by L. D., the short diameter by S. D., and the thickness by T. The average sizes only are given; but it should be understood that many are a third larger and a third smaller than the mean, and a few occasionally still more deviating from it, while there is every gradation of size between the extremes; still the majority of the corpuscles are of the average size. And all this is true of the red blood-corpuscles of most vertebrates. The animals are here set down in the order of the largeness of these corpuscles, except when this would confuse species of different genera of the Frogs and Toads. L. D. S. D. Amphiuma tridactylum ^ ^ .Nucleus ^3 2000 Proteus anguinus ^ ^f Nucleus Ym> 2m Siren lacertina 425 ^ .Nucleus j-j-42 rjQQj Sieboldia maxima ^ ^ Menopoma alleghaniense ^ i^, Nucleus J333 2286 Lepidosiren annectens ^ 9^ Nucleus lis 2L Siredon humboldtii gyj l(^ Nucleus 2000 aooo 11* |