106 



HARDWICKE'S SCIENCE-GOSSIP. 



[May 1, 1S6S. 



In their normal position the tubes are crowded 

 together into a close and even cushion. 



Eour at least of the six spinnerets of the garden 

 spider are furnished with large tubes : they occupy 

 nearly the whole of the small central spinnerets. 

 The house-spider, which spins non-viscid webs, has 

 none. This bead of dark viscid gum will retain its 

 adhesive properties for months, being mixed in 

 large proportion with the viscid and saline fluid 

 which, in the form of minute globules, studs the 

 elastic bars of the web. (For further particulars 

 of which, a paper towards the close of the first 

 volume of Science Gossip, p. 65, may be referred 

 to.) What can be the source of this copious supply 

 of fluid poured out so freely upon every new web 

 is a'very interesting inquiry. 



r 



Fip. 10". Spinneret of Garden Spider x 50. 

 a, Gum-tube ; b, Spinning-tube ; c, c, Hairs. 



There are certain secreting organs in the abdomen 

 of the common spider which have been a subject of 

 controversy among comparative anatomists. Some 

 have supposed them to be analogous to the biliary 

 organs in other insects ; but in this case they pour 

 their secretion into the rectum, just above the vent, 

 and so near to the lower termination of the intes- 

 tine that they seem to furnish nothing to the 

 internal functions of the insect. Others, again, 

 have called them renal vessels, from their resem- 

 blance in position to the urinary organs of the 

 higher animals. (See Jones's " General Structure 

 of the Animal Kingdom," sec. 960, ed. 1864, and 

 the figures there given.) 



The discoveries since made as to the constituents 

 of the web open a new and more probable conjec- 

 ture. Here are secreting organs which anatomists 

 have been unable satisfactorily to assign a use for a 

 but which, or some such, are requisite for the com- 

 pletion of the web. The vent is, then, very probably 

 the main source of the viscid fluid, and from this it 

 is poured upon the elastic cross-bars as they are 

 drawn out under the abdomen of the insect; the 

 vent being close to and immediately behind the 

 spinning apparatus. 



It remains to be proved that these secretiug 

 organs are peculiar to the species forming viscid 

 webs. My own attempt, with this view, on the 

 dissection of the house spider has failed for want of 

 skill : it must be the work of a more practised 

 hand. This point proved, in accordance with my 

 supposition, the problem of the spider's web, so 

 long a difficulty to naturalists, would be in good 

 measure solved. S. S. 



ANIMALS THAT NEVER DIE. 



TNDER the above title, I made some observa- 

 **' tions, in the January number of Science- 

 Gossip, on the process of self-division in certain 

 worms belonging to the genera Nais and Syllis, in 

 regard to which your correspondent " J3. C." accuses 

 me of " inaccuracy in my description," and of 

 " stultifying my results " by the use of the word 

 " if." I have no wish to occupy valuable space in 

 so personal a matter as this ; nevertheless, I hope 

 I may be allowed to place my words in juxtaposition 

 with those of " B. C," that others may see that, if 

 the charge be true, it is a case in which the Horatian 

 maxim is peculiarly applicable, 



Mutato nomine, de te 

 Fabula narratur. 



What I stated was this, that "at certain periods 

 in the life of these animals, the posterior portion of 

 the body begins to alter its shape. ... At last, 

 just at the point where it joins the first half of the 

 body, a true head is formed .... and forthwith the 

 whole drops off— a complete animal capable of main- 

 taining a separate existence." 



Now what says "B. C"? After describing a gene- 

 rative process, which (except on the most superficial 

 view) has nothing to do with the subject before us 

 he writes — (I omit a few sentences which are not 

 descriptive), — " I have frequently watched the pro- 

 cess (viz., of self-division) in Nais prohoscidea and 

 Nais serpentina, but could never satisfy myself tha t 

 the new-formed segments differed in any respect from 

 the anterior moiety. ... It seemed to me that in 

 neither the old or new parts of individuals under- 

 going fission were ova or spermatazoa present. . . . 

 The species is capable of indefinite extension by a 

 sexual fission or budding. . . . The section generally 

 akes place near the centre of the body, the head 

 portion forming a new tail, and the tail portion a 

 new head. ... In a few days, it is impossible to 

 say which individual was derived from the head, 

 which from the tail." Wherein, let me ask, does 

 " B. O's " description differ from mine ? 



Every one has a right to draw his own conclusions 

 from what Nature places before his eyes. I believed 

 it fair to infer (and I cannot see that I have 

 violated the laws of logic in so doing) that if this 

 process goes on for ever (that is, if the posterior 



