In addition to the eyes and the olfactory circle on the head scattered tactile papillae are found on the ectoderm.
The Heteropoda are further remarkable for the high development of their cephalic eyes, and for the typical character of their osphradium (Spengel's olfactory organ).
Each of the visceral ganglia is connected or combined with an olfactory ganglion underlying an area of specialized epithelium, which constitutes the olfactory organ, the osphradium.
Von Kdlliker's olfactory pit.
The hemispheres are rather elongated and subcylindrical, the olfactory lobes are large and project freely in front of the' hemispheres, and the greater part of the cerebellum is uncovered.
Spengel showed that the parabranchia of Gastropods is the typical olfactory organ or osphradium in a highly developed condition.
Nez), the organ of the sense of smell in man and other animals (see Olfactory System).
A pair of eyes lie dorsally and behind them is a b closed circlet, often pulled out into various shapes, of modified epidermis, to which an olfactory function has been attributed.
It is said that 13,000 such olfactory organs are present on the feeler of a wasp, and 40,000 on the complex antennae of a male cockchafer.
In their simpler condition they are long and many-jointed, the segments bearing numerous olfactory and tactile nerve-endings.