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SCIENCE. 



[N. S. Vol. XII. No. 301. 



and nose is also distinctly appreciable. The 

 odor is even more disagreeably pungent and 

 penetrating than that of Spirostreptus and 

 has an almost nauseating quality which 

 pervades the nests and galleries of the spe- 

 cies and can readily be detected in houses 

 attacked by this termite. [Isonitriles ?] 

 Like the secretion of Polyzoniwn the liquid 

 becomes sticky on exposure to the air, and 

 the insect enemies upon which it is squirted 

 have their antennse stuck to their bodies and 

 are otherwise disabled. 



Another comparable secretion exists in 

 the suborder Geophiloidea of the class Chil- 

 opoda which includes the centipedes and 

 their allies, now no longer supposed to have 

 more than the remotest afi&nity with the 

 Diplopoda. The Geophiloidea are long, 

 slender, carnivorous animals, having from 

 31 to 173 leg-bearing segments, the number 

 being always uneven. They live in the 

 ground or in the crevices of decaying wood, 

 coming to the surface only at night. In 

 neai'ly all the species the ventral plate of 

 each segment is perforated by minute pores 

 which are the openings of unicellular glands. 

 In one species, Orphnceus p)hosphoreus, com- 

 mon in the tropics, the secretion which 

 flows from these pores has attracted consid- 

 erable attention because of its brilliant 

 luminosity, the animal leaving behind it a 

 trail of greenish light. Several other spe- 

 cies of different families are known to give 

 off light and that power is probably general 

 in the suborder. Although supposed to be 

 a sexual phenomenon, the purpose of this 

 luminosity, as in the diplopod mentioned 

 above, is scarcely thus explainable, since 

 all the Geophiloidea are, like the Merocheta, 

 quite eyeless. The parallel goes, moreover, 

 a step farther, since the liquid which exudes 

 from the ventral spores of the Geophiloidea* 



* This observation was made and has been verified 

 on two or three occasions with Geophilus rtibens Say, 

 of which G. cephalicus "Wood is a synonyn. The spe- 

 cies is common in northeastern North America. 



has also an odor closely similar if not iden- 

 tical with that of prussic acid, though like 

 the repugnatorial fluid of Polyzoniwn and 

 Ptyotermes it soon assumes an elastic con- 

 sistence and may be drawn out in threads. 

 Whether this material has anything to do 

 with the webs which the Geophiloidea are 

 said to spin is not known, but the general 

 function is probably repugnatorial and in 

 this the luminous quality might also be of 

 use. The tendency of so many of these 

 secretions to become fibrillar also sug- 

 gests mention of the fact that in the. dip- 

 lopod suborder Chordeumatoidea, where re- 

 pugnatorial pores are absent, silk-glands 

 are present, though they can scarcely 

 have any morphological relationship to the 

 pores. 



But leaving these unknown substances 

 out of further account, the fact that cam- 

 phor and prussic acid are quite unrelated 

 chemically is a matter of interest from the 

 evolutionary standpoint. !N"o doubt has 

 ever been expressed that the repugnatorial 

 pores are exact homologues throughout the 

 class Diplopoda, outside of which no mor- 

 phological equivalents have been recog- 

 nized. That organs of common origin 

 should produce for the same purposes sub- 

 stances so utterly unlike is a fact that seems 

 very difficult of explanation by existing 

 theories, either from the biological or from 

 the chemical standpoint. For the equip- 

 ment of pores derived from a common an- 

 cestral type and having maintained their 

 repugnatorial function, it would seem 

 necessary to predicate a gradual change of 

 secretion from camphor to prussic acid or 

 from prussic acid to camphor, or from some 

 intermediate substance to these two and to 

 the other unknown derivatives. We have, 

 in fact, a chemico-biological question which 

 can be placed on a genuine phylogenetic 

 basis, the problem being to construct a 

 chain of evil smelling or at least aromatic 

 substances to connect camphor with prussic 



