:hap. xx.] 



EXTRA LEGS : POSITION V. 



483 



vith the Position V and taking the other radii in order, going 

 ound against the hands of a watch. 



Cases of Extra Legs ix Secondary Symmetry. 



(1) Position V. 



Carabus scheidleri % : pair of extra legs having a common 

 emoral^ portion arising from the trochanter of the right fore leg- 

 Fig. 155). This case is of diagrammatic simplicity. The troch- 



Fig. 155. Carabus scheidleri, Xo. 736. The normal right fore leg, R, bearing 

 a extra pair of legs, SL and SR', arising from the ventral surface of the coxa, C. 

 een from in front. (The property of Dr Kraatz.) 



nter bears a normal leg (R) articulating as usual. Immediately 

 entral to this articulation there is a second articulation upon a 

 mall elevation. This bears a double femur made up of parts 

 f a pair of femora compounded by their dorsal borders. The 

 ouble femur has thus two structurally ventral surfaces opposite 

 } each other. 



The apex presents two articular surfaces in the same plane 

 s that of the normal leg, each bearing a tibia, both tibiae flexing 

 l the same vertical plane. 



Since the double femur of the extra legs stands vertically 

 ownwards at right angles to the normal femur, it will be seen 

 lat both the extra tibiae flex upiuards, but one of them is a 

 sft leg (SL), bending to meet the normal leg, while the other 

 ; a right (SR'), bending towards the ventral surface of the body, 

 he tibia of the left extra leg is a little shorter than that of 

 le normal, and the tibia of the right extra leg is a little longer 

 lan it. All three tarsi are thinner than a normal tarsus ; and 

 le claws are a good deal reduced in the case both of the normal 

 ad the right extra leg, while in the left extra leg they are absent 

 together. This is an example of a pair of extra legs arising 



31—2 



