234 Mr. J. Blackwall on the Structure , Functions 



the following July it cast its integument and reproduced the right 

 palpus, which, though small, had the digital joint very tumid. It 

 moulted again on the 20th of August, in the same year, when the 

 dimensions of the right palpus were augmented, the radial joint was 

 provided with an apophysis, and the sexual organs were developed. 

 The organization of the right palpus was perfect in all its parts, but 

 they were smaller than the corresponding parts of the left palpus. 



15. On the 25th of June 1841 a young male Drassus sericeus had 

 the cubital, radial and digital joints of the left palpus amputated, the 

 digital joint being very tumid. It moulted on the 16th of the en- 

 suing August and reproduced the left palpus, of a small size ; the 

 radial joint was provided with an apophysis, indicating the mature 

 state of the spider, but the sexual organs were not reproduced. 



16. A young male Cinifioferox had the right palpus amputated 

 at the axillary joint on the 2nd of July 1841. On the 19th it 

 moulted, but the stump only of the mutilated part was produced. 

 On the 28th of the same month the left palpus was amputated at the 

 axillary joint. The spider moulted again on the 28th of the ensuing 

 August, when both the palpi, of a small size, were produced. 



17. The anterior leg on the left side of a young female Tegenaria 

 civilis was amputated at the coxa on the 1st of September 1842. 

 This spider was dissected on the 14th of the following October, when 

 on the point of moulting, as was evident from the deepened hue of 

 the integument and from the perfect structure of the tarsal and pal- 

 pal claws, visible through it. The anterior leg on the left side, which 

 was reproduced, was complete in its organization, /^ths of an inch 

 in length, and was curiously folded in the integument of the old 

 coxa, which measured only ^^^h of an inch in length. 



18. A young male Tegenaria civilis had the posterior leg on the 

 left side amputated near the middle of the tibia on the 24th of April 

 1843, when it moistened the tarsus of the third leg on the same side 

 with saliva and repeatedly applied it to the mutilated limb. Being 

 about to moult, this spider was dissected on the 5th of the ensuing 

 June ; the posterior leg on the left side, which was reproduced, was 

 found to have its tarsal and metatarsal joints folded in the undetached 

 half of the integument of the old tibia. 



A recapitulation of the more remarkable results obtained from 

 the experiments^ elucidated in several instances by additional facts 

 and observations, will not, it is presumed, be deemed superfluous. 



Physiologists, in conducting researches relative to the reproduc- 

 tion of the limbs of spiders, seem to have limited their investigations 

 to the legs of those animals ; whereas, in the experiments detailed 

 above, the palpi and spinners, as well as the legs, were operated 

 upon ; and all these parts are found to be renewed, and afterwards 

 to have their dimensions enlarged at the period of moulting only ; 

 it appears also that if a part of a limb be amputated, as the tarsus 

 of a leg or the digital joint of a palpus, the whole is reproduced, all 

 the joints of the new limb, though small, being proportionate to those 

 of the corresponding limb on the opposite side, with the exception of 

 the digital joint of the palpi of male spid<=rs when the sexual organs 



