On a Peculiar Sense Organ in Scutigera 

 coleoptrata, one of the Myriapoda. 



By 



F. e. Heathcote, B.A., 



Trinity College, Cambridge. 



With Plate XX. 



In the spring of the year I was fortunate enough to get a 

 fair number of Scutigera in the South of Europe. In making 

 an examination of their anatomy I found a sense organ which 

 seemed to me to be of sufficient interest to render a more com- 

 plete examination desirable. This organ is placed on the 

 ventral surface of the head at a short distance behind the 

 mouth and near the base of the mandibles. Its external 

 appiearance under a low power of the microscope (Zeiss's 

 objective a a) is shown in fig. 1. 



General Featukes. 



The organ which was first mentioned by Latzel, consists of 

 a chitinous sac with a slit-like opening (fig. 1, eo.). The 

 opening is placed between the base of the mandibles and the 

 maxillae. The sac has a somewhat complicated form which 

 will be best understood by reference to four diagrams (see 

 plate XX, figs. A, B, c, d. 



The first of these shows a rough outline of the appearance 

 of the organ from the ventral side ; the second, third, and fourth 

 being diagrammatic sections through the dotted lines AB, CD, 

 and EF. £ is a transverse section through the anterior portion 

 of the organ. It shows the main sac communicating with the 



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