PECULIA'B SENSE QBQAN IN SCDTIGBfiA COLEOPTEATA. 197 



Conclusions. 



The active predatory habits of this Myriapod and its power 

 of swift locomotion would seem to render well-developed sense 

 organs a necessity to it; in fact it has facetted eyes in place 

 of the simple eye-spots of most Myriapods. 



The organ above described must, I think, be included among 

 the great number of widely dissimilar organs usually classed 

 together as auditory, and may be compared to the tympanic 

 organ of insects. 



The auditory organs of insects have been investigated prin- 

 cipally by v. Siebold (' Archiv fur Naturg.,' 1844), Leydig 

 ('Miiller's Arch.,' 1855 and 1860), v. Hensen ('Zeitschr. f. 

 wiss. Zool.,' tom. xvi, 1866), and v. Graber (' Denkschr. der K. 

 Akad. der Wissensch.,' Wien., 1875). The tympanic organ of 

 the Acridiidae consists essentially of a tympanic membrane sup- 

 ported by a chitinous ring. Places in the tympanic membrane are 

 thickened, so as to form solid chitinous pieces of peculiar form, 

 the internal surface of which is covered with indentations in 

 which the extreme ends of the sensory apparatus end (Fr. 

 Leydig, ' Miiller's Archiv,' 1855, p. 401). The auditory nerve 

 spreads out on these chitinous pieces and forms a ganglion, 

 from which fibres ending in peculiai' sense cells are given off. 

 A trachea lies close to the ganglion internally to it, and not 

 unfrequently swells to a vesicle. 



On comparing the organ of Scutigera with such an organ 

 there is found to be a great similarity in the general plan. 

 Each pouch in Scutigera represents the insect tympanum. 

 In both cases we have a thick nerve breaking up into a number 

 of sensory elements, which end in depressed spaces in the 

 chitinous membrane. With regard to the chitin hairs which 

 project through the chitin in Scutigera, I think it will be 

 worthwhile to consider Hensen's investigations on the auditory 

 rods of insects (Horstifte, v. Hensen, 1. c). He makes an 

 interesting comparison between these structures and the audi- 

 tory hairs of the crustacean auditory sac, and draws the con- 



