424 MB. H. M. BERNARD ON THE CHERNETID^. 



somewhat like a i-am's-horn (fig. 12). The organs in my speci- 

 men are beset with air-chambers closely packed between the 

 muscles and inner organs, wherever, in fact, there has been room 

 for their development. 



Croneberg describes these organs as being invested by an epi- 

 thelium of " small cells '008 millim. high." I could not find any 

 very clear traces of this epithelium, but the air-chambers appeared 

 to be developed within cells, the nuclei of which could occasionally 

 be seen in a fine layer of protoplasm (fig. 12 a). 



Menge, who recognized their remarkable likeness to tracheae, 

 believed these organs to be transmitters of sperm, and says that 

 they are sometimes found turned inside out like the finger of a 

 glove, and protruding from under the genital operculum; and 

 Simon * has a figure in which they are seen hanging out, ex- 

 tending one to the anterior and the other to the posterior end of 

 the body ! Whatever this evagination of these tubes may mean, 

 it certainly requires investigation, but in the meantime the mere 

 fact of their opening under the genital operculum in no way 

 necessitates their having any connection with reproduction, as 

 Croneberg seems to think, although he inclines to the belief that 

 they are homologous with tracheae. The view that they are 

 transmitters of sperm, the latter finding its way into the tips of 

 the tubes which are theu evaginated, seems on the face of it so 

 very improbable that it could be accepted only on the most un- 

 mistakable evidence. 



"We have, then, the two views : — (1) The old view that they 

 are reproductive; and (2) the suggestion here made that they 

 are respiratory. 



In favour of the first view, we have the following arguments : — 



{a) They occur under the genital operculum, close to the 

 genital aperture. 



(l) They have no protective stigmata. 



(c) They are often found evaginated. 



{cl) They are said to be confined to the males. 



In favour of their being respiratory, the following arguments 

 may be used : — 



(a) Their resemblance to tracheae. 



(6) Their position under the genital operculum, i. e. in close 

 connection with rudimentary limbs, which is typical of tracheae. 



(c) Their occurrence on the 1st abdominal segment is quite 



* ' Les Arachnides de France,' vol. viii. 1879, p. 3, pi. xyii. fig. 4. 



