CHAP. XX.] 



EXTRA LEGS : POSITION V. 



483 



with the Position V and taking the other radii in order 

 round against the hands of a watch. 



CASES OF EXTRA LEGS ix SECONDARY SYMMETRY. 

 (1) Position V. 



*736. Carabus scheidleri $ : pair of extra legs having ;l ,-nnmion 

 femoral portion arising from the trochanter of the right fore leg 

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



FIG. 155. Carabus scheidleri, No. 736. The normal right fore leg, R, 

 an extra pair of legs, SL and Sit', arising frorn the ventral -uituo nt' tin coxa, (.'. 

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



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

 ventral to this articulation there is a second articulation \\\>\i a 

 small elevation. This bears a double femur made up nf part- 

 of a pair of femora compounded by their dnr-al lmrd<T- Tin- 

 double femur has thus two structurally ventral surface- 

 to each other. 



The apex presents two articular surfaces in the same plane 

 as that of the normal leg, each bearing a tibia, both tibia- flexing 

 in the same vertical plane. 



Since the double femur of the extra legs stands vertically 

 downwards at right angles to the normal femur, it will lie seen 

 that both the extra tibia? hVx H Awards, but me nf them is a 

 left leg (SL), bending to meet the iiunnal leg. while the ntln-r 

 is a right (SR'), bending towards the ventral surface nf the bndy. 

 The tibia of the left extra leg is a little shorter ih:m that <f 

 the normal, and the tibia of the right extra leg is a little l.m^er 

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

 the claws are a good deal reduced in tin- case l.th <>f tin- imnn;d 

 and the right extra leg, while in the left extra leg they are aWnt 

 altogether. This is an example of a pair nf .-xtra le-s an-m- 



312 



