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sharp line to be drawn between the ganglion cells of the organ and the 
brain. The rods are delicate and covered with small nuclei very well 
supplied with chromatin. 
To what has already been made known by Weismann and Hurst on 
the general development of the antenna in these insects, Mr. Child 
adds that the entire sense organ is formed from a fold at the base of 
the invaginated hypodermal cavity, and that the differentiation of the 
rods and ganglion cells takes place very early. 
The organ he considers to be auditory in function, agreeing with 
Johnston, Mayer and Hurst! Supporting this view is the fact that 
the rods are so placed as to be affected by any slight motion imparted 
to the distal part of the antenna, either by sound waves or otherwise. 
It has been repeatedly shown by others that certain insects seem to 
hear by means of their antenns. To offset the fact that the so-called 
tympanum of certain Orthoptera is considered to be auditory he recalls 
the experiments by Graber, who found that insects in which the 
tympanum bad been destroyed still reacted to sound waves which 
affected the antennz or in some cases the legs. The organ is of further 
interest in that there is shown in it no marked difference between hear- 
ing and touch.—F. C. Kenyon. 
The Luminous Organs of Histioteuthis rueppellii Verany. 
—Dr. Joubin has recently been making a study of the luminous organs 
of a rare cephalopod, Histioteuthis rueppellii, found near Nice. The 
animal belongs to the abyssal fauna and the specimen in question is 
over a meter in length. "The author describes the outward appearance 
of its phosphorescent organ, and its internal organization, comprising a 
reflector, which the author calls a mirror and an apparatus for produc- 
ing light. Mr. Jourbin offers the following theory of the use of the 
luminous organ to the animal. 
“ Ordinarly the light-producing apparatus does not function. It is 
like a machine at rest. But if a living creature suitable for food 
wanders into the vicinity of the cephalopod, this prey being of a higher 
temperature than the water in which it floats emits caloric radiations. 
These heat rays impinge on the reflecting mirror and are then concen- 
AJ ohnston. PME Apparatus of the Culex Mosquito. Journ. Mier. Sci. 
IH, old seri 
Mayer. es chesin acoustics. Am. Journ. Sc. Series III, vol. 8. 
Hurst.—The Pupal Stage of un Inaug.-Diss. Leipzig, 1890.—On the Life 
History and Development ofa gnat. Trans. Manchester, Micro. Soc., 1890. 
The Post-embryonic Development of Culex. Proc. Liverpool Biol. Soc. IV. 
