15G H. F. JAYNE. 



CycliPiis angusticollis, Fisch. 



Fig. 2 represents the deformed left auterior leg of a specimen of 

 Cj/chriis nngusticollis. The femur is greatly dilated a little beyond 

 the middle and gives off from it superior border a tubercle moder- 

 ately long and blunt at tip. This may possibly indicate an attempt at 

 the development of a second leg. The femur is then narrowed and 

 at apex is a little lai-ger than the apex of the normal joint. The 

 existence of a cotyloid cavity shows the former presence, and acci- 

 dental loss, of the tibia. 



In the Museum of Comparative Zoology at Cambridge. 



Metrias contractus, Esch. 



A monstrosity in the middle left leg of a specimen of 31etrius con- 

 tractus is shown in fig. 3. The femur bears two tibias the inner one 

 bearing two full sets of tarsal joints. The femur is normal. The 

 outer tibia, which may be regarded as the normal one arises from the 

 extremity of the femur and is somewhat shorter, stouter, and more 

 curved than the tibia of the middle right leg. The inner tibia arises 

 from the posterior side of the femur a short distance within the tip 

 and is articulated with it by a separate cotyloid cavity, the two cavities 

 however are confluent as seen in fig. 3 a. It is distinctly arcuate, 

 dilated toward the apex which is obli(juely truncate at each angle. 

 From each facet thus formed arises a tarsal joint of normal length, 

 almost contiguous at their bases, and somewhat stouter than the 

 succeeding joints which are normal in form but shorter than those of 

 a normal tarsus. There are four terminal spurs to this tibia, two 

 placed external to the outer tarsus, two within the inner. 



In Dr. Horn's Collection. 



Pasimaclms punctulatns, Hald. 

 A specimen o^ Fasimachus punctalatus has seven legs; the extra 

 one arising from a trochanter placed between the normal trochanter 

 and femur of the left middle leg. Fig. 4 represents the anomaly as 

 seen from below. The coxa and trochanter are like those of the right 

 leg. On the inferior surftice, between the trochanter and femur and 

 embraced in front and behind by the latter, is inserted a second 

 trochanter ; triangular in form, about half as wide and one-third as 

 long as the normal one. It gives origin to the extra femur, which is 

 two-thirds as long and about three-fourths as stout as the main thigh. 

 The tibia of this extra femur is perfect except that it is one-fourth 

 shorter than the other; its spurs and tarsal joints, and the claws 



