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In those places where in mammals scales occur, the hairs are inserted 
generally in groups behind them. In this point they therefore differ from 
the thighorgans, which are placed in the middle of scales. It is true, that 
not too much value ought to be attached to this fact, but yet I want to 
point out in the first place that the afore-mentioned dermal organs 
of the crocodiles, described by Vorurzkow, are arranged between 
the scales, and further, that the similarity in location of hairs and 
femoral organs becomes greater, if the considerations of Prnkus*) in 
connection with the “hairdises” described by him, are right. If, as 
he thinks, a “Haarbezirk’”, that is the whole complex of scale 
rudiment, hair group and hairdisc, answers to the scale of reptiles, 
then the hairs are placed in the middle of the region of the scale, 
just the same as is the case with the thighorgans. Pinkus, who 
derives the hairdises from tactile spots of reptiles, cannot find an 
explanation for the origin of the hairs: “Das Säugetierhaar hat 
kein Homologen in dem Gebiet der Reptilienschuppe; sein Platz 
ist leer.” By the hypothesis, developed before, this objection against 
Pinkus’ theory is done away with. 
Maurer has directed the attention to another arrangement of the 
hairs; still before the hairgroups are formed, in mammalian embryos 
the placing of hairs in longitudinal rows may be stated. From this 
fact Maurer deduces an argument for his before mentioned theory, 
because epidermal sense organs generally show a similar arrange- 
ment. This argument however becomes worthless by the observation 
Fig. 1 Lacerta agilis. Bundle of three femoral organs (1—3). 
') Arch. f. mikrosk. Anat., LXV, 1905. 
