TRANSACTIONS OF THE SECTIONS. 67 



Many spiders employ their palpi in assisting to collect into a small heap the slack 

 line which results from their operations when engaged in ascending or drawing in 

 such silken filaments as are attached to objects distinct from themselves by one ex- 

 tremity only. 



In conjunction with the mandibles, the palpi are employed by females of the species 

 Dolomedes mirabilis and Dolomedes fimbriatus to retain their cocoons under the sternum, 

 in which situation those spiders usually carry them wherever they move ; the Lycosce- 

 also avail themselves of the same parts in regaining possession of their cocoons when 

 detached from the spinners. 



Various species belonging to the genus Salticus, to which distinctness and ac- 

 curacy of vision are of the utmost consequence, as they do not construct snares, but 

 capture their prey by springing suddenly upon it from a distance, have the terminal 

 joint of the palpi abundantly supplied with hairs, and constantly make use of those 

 organs as brushes to remove dust, or any other extraneous matter, from the corneous 

 coat of the anterior eyes. 



The palpi appear to afford direct assistance likewise to spiders in general in se- 

 curing their prey, in changing its position while they are feeding upon it, and in re- 

 straining the action of the wings of all their victims which happen to be provided 

 with them. 



At the meeting of the Association held at Cambridge, the author communicated to 

 the Section of Zoology and Botany the results of experiments having for their object 

 the determination of the function performed by the remarkable organs connected with 

 the. terminal joint of the palpi of male spiders *. 



Since that period he has greatly extended and varied his researches in connexion 

 with this subject, and it affords him satisfaction to state, that they promise, when 

 complete, to divest the matter of all uncertainty whatever; indeed, from the decisive 

 character of the evidence at present in his possession, he does not hesitate to assert 

 positively that the palpal organs, whose full development indicates a state of ma- 

 turity, are the only instruments employed by male spiders in the propagation of their 

 species. 



The several joints of the palpi of female spiders differ greatly in their relative pro- 

 portions, not only in species constituting the same family, but even in those belong- 

 ing to the same genus ; while, on the other hand, it frequently happens that females 

 belonging to different genera bear a striking resemblance to each other in this 

 particular. 



It is among male spiders, however, that these peculiarities are the most marked, 

 and to them may be added structural differences and resemblances both of the palpi 

 and palpal organs still more conspicuous. 



A great similarity in the form of the palpal organs and in the manner in which they 

 are connected with the digital joint of the palpi may be observed in certain spiders of 

 the family Dysderidee ; in Dysdera erythrina, Dysdera Hombergii, Segestria perfida, 

 Segestria senoculata, and Oonops pulcher, for example; and this similitude is extended 

 to various species belonging to the family Mygatidce. 



Between Manduculus ambiguus and Tetraguatha externa there is a near approxi- 

 mation in the structure of the palpi and palpal organs, yet these spiders are not in- 

 cluded in the same family, the former belonging to the Theridiidce and the latter to 

 the Epeiridce. 



If we compare the spiders constituting the genus Clubiona with those of the genus 

 Drassus, and those of the genus Linyphia with the species comprised in the genus 

 Neriene ; or, extending the investigation still further, if we compare together the 

 genera JValckenaera, Theridion, Epe'ira, Eresus, Salticus, Thomisus, and Philodromus, 

 numerous instances of correspondence in the relative proportions of the joints of the 

 palpi will be perceived immediately, at the same time striking contrasts will present 

 themselves to the eye of the observer, not as regards proportion alone, but organiza- 

 tion also, even among nearly allied species. 



From these facts the following practical results appear to be fairly dedu- 

 cible : — 



As the full development of the palpal organs indicates a state of maturity in male 

 spiders, the skilful arachnologist is enabled, by attending to this circumstance, not 



* See Report for 1833, p. 444. 

 f2 



