On the Auditory and Olfactory Oryans of Spider <i. 329 



ITab. Seychelles Islands [Dr. E. Perceval WriyJit). 



The nearest ally of this species is C. fusiforniis, Reeve, from 

 which it may be distinguished Ly the sliarper angulation of 

 the whorls, more attenuated body-whorl, tiner liration on the 

 columella, and the slightly longer spire. The slight sinus 

 towards the lower part of the labrum is comparatively con- 

 spicuous. 



XL. — T/ic Auditory and Olfactory Organs of Spiders. 

 By Friedrich Dahl*. 



[Plate XII.] 



Last year I published, in the ' Zoologischer Anzeiger ' 

 (p. 267), a short communication upon some peculiarly articu- 

 lated hairs in the Arachnida, which I interpreted as an organ 

 of hearing. I have since continued my investigations upon 

 this subject, as also upon the sense-organs of the spiders 

 in general, and venture here to make known some further 

 results. 



In the first place I ascertained that the spiders have not 

 only auditory but also olfactory perceptions, and after long 

 seeking I succeeded in discovering in the maxillffi an exceed- 

 ingly peculiar organ which, for reasons presently to be given, 

 I think may be regarded as the olfactory organ. 



But before proceeding to its description I would make some 

 additions to the exposition of both the histological structure 

 and the systematic significance of the auditory hairs, and also 

 replace the indifferent woodcut representations with better 

 drawings. 



As I have already mentioned in the above-mentioned article, 

 the auditory hairs occur upon the upper surface of the legs 

 and palpi. I also indicated that with reference to these hairs 

 our indigenous spiders may be divided into two groups. I 

 have since examined, in connexion with this, nearly all the 

 spiders that were at my disposal in a suitable state, and I can 

 not only sustain the assertion then made, but can also make 

 some further remarks upon the classification of the Spiders by 

 the employment of this character. 



The first group, which has been already separated upon 

 other characters from the other spiders, 1 characterized as 

 follows : — 



* Translated bv W. S. Dallas, F.L.S., from the ' Archiv fiir inikro- 

 ekopische Anatomie,' Band xxiv. pp. 1-10. 



