The Internal Anatomy of Spiders 



cell is elongate, with a nucleus at its proximal end, near its con- 

 nection with a nerve, and with the distal end long and slender, 

 and extending to the thin layer of cuticula limiting the slit within. 

 According to Bertkau ('78), who discovered these organs, the 

 nerve-end-cell terminates in a small chitinous rod which rests 

 against the thin layer of cuticula; but this rod is not described 

 by later writers, and is not now believed to exist. 



The observations of Bertkau led to the belief that the lyri- 

 form organs are auditory in function. But the failure of other 

 observers to discover scolopalae or auditory pins in the nerve- 

 end-cells connected with them has made this conclusion doubtful. 

 A detailed description of the lyriform organs has been pub- 

 lished by Mr. N. E. Mclndoo since the preceding account was 

 put in type. (Proc. Acad. Nat. Sci. Phil. 191 1, pp. 375—418). 

 The results of Mr. Mclndoo's experiments indicate that the 

 lyriform organs are olfactory in function. 



e. THE ORGANS OF TOUCH 



The organs of touch of spiders are distributed generally 

 over the surface of the body. They are hollow hairs or setae 

 each furnished with a nerve. The structure of such hairs has 

 been described on page 140, and is illustrated by Fig. 146. 



It is probable that the nerves of the hairs are connected with 

 a subhypodermal nerve-plexus as is well-known to be the case 

 with insects. Traces of such a nerve-plexus have been observed 

 by Bernard ('96) in the Solpugida. 



/. THE ORGANS OF TASTE AND OF SMELL 



Very little has been written regarding the organs of taste 

 and of smell of spiders; and it is still a question whether organs 

 of either of these senses exist among spiders or are wanting. It 

 may be, as indicated above, that the lyriform organs are olfactory. 



THE GLANDS OF SPIDERS 



With the exception of the poison glands and the silk glands, 

 the glands of spiders have received comparatively little attention. 

 The moulting of spiders has been described in great detail by 

 Wagner ('88); and reference is made by him to the moulting fluid 



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