PECULIAR SENSE ORGAN 11$, SCUTIGERA COLEOPTRATA. 235 
On a Peculiar Sense Organ in Scutigera 
coleoptrata, one of the Myriapoda. 
By 
F. G. Heathcote. B.A., 
Trinity College, Cambridge. 
With Plate XVIII. 
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 
appearance under a low power of the microscope (Zeiss's 
objective a a) is shown in fig. 1. 
General Features. 
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, pp. 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. B is a transverse section through the anterior portion 
of the organ. It shows the main sac communicating with the 
